diff --git a/src/app/(campaign)/campanha/(app)/atividades/[slug]/ActivityOverviewTab.tsx b/src/app/(campaign)/campanha/(app)/atividades/[slug]/ActivityOverviewTab.tsx
index fbe402aa..2b53a939 100644
--- a/src/app/(campaign)/campanha/(app)/atividades/[slug]/ActivityOverviewTab.tsx
+++ b/src/app/(campaign)/campanha/(app)/atividades/[slug]/ActivityOverviewTab.tsx
@@ -2,6 +2,7 @@ import { PlusIcon } from 'lucide-react'
 import Link from 'next/link'
 
 import { ActivityResultForm } from '@/components/campaign/activity/ActivityResultForm'
+import { CampaignListPagination } from '@/components/campaign/shared/CampaignListPagination'
 import { Badge } from '@/components/ui/Badge'
 import { Button } from '@/components/ui/button'
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
@@ -17,6 +18,12 @@ const currencyFormatter = new Intl.NumberFormat('pt-BR', {
 
 type ActivityDetailView = Awaited<ReturnType<typeof getActivityDetailPageData>>
 
+const hrefForLinkedDemandsPage = (activitySlug: string, page: number) => {
+  const params = new URLSearchParams({ tab: 'overview' })
+  if (page > 1) params.set('demandsPage', String(page))
+  return `/campanha/atividades/${activitySlug}?${params.toString()}`
+}
+
 /** The "Visão geral" tab: details, team/orgs, linked demands and the result block. */
 export const ActivityOverviewTab = ({
   view,
@@ -128,47 +135,67 @@ export const ActivityOverviewTab = ({
           <CardTitle>Demandas vinculadas</CardTitle>
           <p className="text-sm text-muted-foreground">
             Custo estimado: {currencyFormatter.format(view.demandCostTotal)}
+            {view.totalDocs > 0 ? (
+              <>
+                {' '}
+                · {view.totalDocs} {view.totalDocs === 1 ? 'demanda' : 'demandas'}
+              </>
+            ) : null}
           </p>
         </div>
-        {view.municipality ? (
-          <Button asChild variant="outline" className="min-h-11 shrink-0">
-            <Link
-              href={`/campanha/demandas/nova?activity=${view.id}&municipality=${view.municipality.id}`}
-            >
-              <PlusIcon data-icon="inline-start" aria-hidden="true" />
-              Adicionar demanda
-            </Link>
-          </Button>
-        ) : null}
-      </CardHeader>
-      <CardContent>
-        {view.demands.length ? (
-          <ul role="list" className="divide-y">
-            {view.demands.map((demand) => (
-              <li
-                key={demand.id}
-                className="flex flex-col gap-2 py-3 first:pt-0 last:pb-0 sm:flex-row sm:items-center sm:justify-between"
+        <div className="flex shrink-0 flex-wrap gap-2">
+          {view.totalDocs > view.demands.length ? (
+            <Button asChild variant="ghost" className="min-h-11">
+              <Link href={`/campanha/demandas?activity=${view.id}`}>Ver todas</Link>
+            </Button>
+          ) : null}
+          {view.municipality ? (
+            <Button asChild variant="outline" className="min-h-11 shrink-0">
+              <Link
+                href={`/campanha/demandas/nova?activity=${view.id}&municipality=${view.municipality.id}`}
               >
-                <div className="min-w-0">
-                  <Link
-                    href={`/campanha/demandas/${demand.slug}`}
-                    className="font-medium text-primary underline-offset-4 hover:underline"
-                  >
-                    {demand.title}
-                  </Link>
-                  <p className="text-sm text-muted-foreground">
-                    {campaignDemandKindLabels[demand.kind]} ·{' '}
-                    {campaignDemandStatusLabels[demand.status]}
-                  </p>
-                </div>
-                <span className="text-sm text-muted-foreground">
-                  {demand.cost == null
-                    ? 'Custo não registrado'
-                    : currencyFormatter.format(demand.cost)}
-                </span>
-              </li>
-            ))}
-          </ul>
+                <PlusIcon data-icon="inline-start" aria-hidden="true" />
+                Adicionar demanda
+              </Link>
+            </Button>
+          ) : null}
+        </div>
+      </CardHeader>
+      <CardContent className="flex flex-col gap-4">
+        {view.demands.length ? (
+          <>
+            <ul role="list" className="divide-y">
+              {view.demands.map((demand) => (
+                <li
+                  key={demand.id}
+                  className="flex flex-col gap-2 py-3 first:pt-0 last:pb-0 sm:flex-row sm:items-center sm:justify-between"
+                >
+                  <div className="min-w-0">
+                    <Link
+                      href={`/campanha/demandas/${demand.slug}`}
+                      className="font-medium text-primary underline-offset-4 hover:underline"
+                    >
+                      {demand.title}
+                    </Link>
+                    <p className="text-sm text-muted-foreground">
+                      {campaignDemandKindLabels[demand.kind]} ·{' '}
+                      {campaignDemandStatusLabels[demand.status]}
+                    </p>
+                  </div>
+                  <span className="text-sm text-muted-foreground">
+                    {demand.cost == null
+                      ? 'Custo não registrado'
+                      : currencyFormatter.format(demand.cost)}
+                  </span>
+                </li>
+              ))}
+            </ul>
+            <CampaignListPagination
+              page={view.page}
+              totalPages={view.totalPages}
+              hrefForPage={(page) => hrefForLinkedDemandsPage(view.slug, page)}
+            />
+          </>
         ) : (
           <p className="text-sm text-muted-foreground">
             Nenhuma demanda vinculada a esta atividade.
diff --git a/src/app/(campaign)/campanha/(app)/atividades/[slug]/page.tsx b/src/app/(campaign)/campanha/(app)/atividades/[slug]/page.tsx
index da5cdeb6..b0ddb88f 100644
--- a/src/app/(campaign)/campanha/(app)/atividades/[slug]/page.tsx
+++ b/src/app/(campaign)/campanha/(app)/atividades/[slug]/page.tsx
@@ -29,6 +29,7 @@ import {
   resolveAccessibleActivityContext,
 } from '@/utilities/activityPageData'
 import { isCampaignStaff } from '@/utilities/campaignAccess'
+import { firstValue, strictDecimalInteger } from '@/utilities/campaignListUrl'
 import { requireCampaignPageActor } from '@/utilities/campaignPageActor'
 
 import { ActivityOverviewTab } from './ActivityOverviewTab'
@@ -57,7 +58,13 @@ export default async function ActivityDetailPage({
       throw error
     },
   )
-  const view = await getActivityDetailPageData(payload, user, context, activeTab)
+  const view = await getActivityDetailPageData(
+    payload,
+    user,
+    context,
+    activeTab,
+    strictDecimalInteger(firstValue(query.demandsPage)) ?? 1,
+  )
   const canonicalTabRedirect = getActivityDetailTabRedirect(view.slug, query)
   if (canonicalTabRedirect) redirect(canonicalTabRedirect)
 
diff --git a/src/app/(campaign)/campanha/(app)/demandas/activitySearchActions.ts b/src/app/(campaign)/campanha/(app)/demandas/activitySearchActions.ts
new file mode 100644
index 00000000..b49d96fe
--- /dev/null
+++ b/src/app/(campaign)/campanha/(app)/demandas/activitySearchActions.ts
@@ -0,0 +1,20 @@
+'use server'
+
+import config from '@payload-config'
+import { getPayload } from 'payload'
+
+import type { AsyncSearchOption } from '@/components/campaign/shared/AsyncSearchCombobox'
+import { searchActivityRelationOptions } from '@/utilities/activityRelationOptions'
+import { getCampaignUser } from '@/utilities/campaignAuth'
+import { CAMPAIGN_AUTH_REQUIRED_MESSAGE } from '@/utilities/campaignFormActionError'
+
+export const searchDemandActivityOptions = async (
+  query: string,
+  municipalityId: number | null,
+): Promise<AsyncSearchOption[]> => {
+  const [payload, user] = await Promise.all([getPayload({ config }), getCampaignUser()])
+  if (!user) throw new Error(CAMPAIGN_AUTH_REQUIRED_MESSAGE)
+
+  const options = await searchActivityRelationOptions(payload, user, query, municipalityId)
+  return options.map((option) => ({ id: option.id, label: option.label }))
+}
diff --git a/src/app/(campaign)/campanha/(app)/demandas/nova/page.tsx b/src/app/(campaign)/campanha/(app)/demandas/nova/page.tsx
index ca266051..c6c99756 100644
--- a/src/app/(campaign)/campanha/(app)/demandas/nova/page.tsx
+++ b/src/app/(campaign)/campanha/(app)/demandas/nova/page.tsx
@@ -3,12 +3,14 @@ import { ArrowLeftIcon } from 'lucide-react'
 import Link from 'next/link'
 import { getPayload } from 'payload'
 
+import { searchDemandActivityOptions } from '@/app/(campaign)/campanha/(app)/demandas/activitySearchActions'
 import { DemandForm } from '@/components/campaign/demand/DemandForm'
 import { CampaignPageShell } from '@/components/campaign/shell/CampaignPageShell'
 import { Button } from '@/components/ui/button'
+import { loadActivityRelationOptionById } from '@/utilities/activityRelationOptions'
 import { firstValue, strictDecimalInteger } from '@/utilities/campaignListUrl'
 import { requireCampaignPageActor } from '@/utilities/campaignPageActor'
-import { loadActivityOptions, loadMunicipalityOptions } from '@/utilities/campaignRelationOptions'
+import { loadMunicipalityOptions } from '@/utilities/campaignRelationOptions'
 import { createDemandFormAction } from './formActions'
 
 type NewDemandPageProps = {
@@ -22,16 +24,16 @@ export default async function NewDemandPage({ searchParams }: NewDemandPageProps
     searchParams,
   ])
 
-  const [municipalityOptions, activityOptions] = await Promise.all([
-    loadMunicipalityOptions(payload, user),
-    loadActivityOptions(payload, user),
-  ])
-  const requestedActivity = activityOptions.find(
-    (activity) => activity.id === strictDecimalInteger(firstValue(query.activity)),
-  )
+  const requestedActivityId = strictDecimalInteger(firstValue(query.activity))
   const requestedMunicipalityId = strictDecimalInteger(firstValue(query.municipality))
+  const [municipalityOptions, initialActivity] = await Promise.all([
+    loadMunicipalityOptions(payload, user),
+    requestedActivityId
+      ? loadActivityRelationOptionById(payload, user, requestedActivityId)
+      : Promise.resolve(null),
+  ])
   const initialMunicipalityId =
-    requestedActivity?.municipalityId ??
+    initialActivity?.municipalityId ??
     municipalityOptions.find((option) => option.id === requestedMunicipalityId)?.id
 
   return (
@@ -52,9 +54,9 @@ export default async function NewDemandPage({ searchParams }: NewDemandPageProps
 
       <DemandForm
         municipalityOptions={municipalityOptions}
-        activityOptions={activityOptions}
+        initialActivity={initialActivity}
         initialMunicipalityId={initialMunicipalityId}
-        initialActivityId={requestedActivity?.id}
+        searchActivities={searchDemandActivityOptions}
         formAction={createDemandFormAction}
       />
     </CampaignPageShell>
diff --git a/src/components/campaign/demand/DemandForm.tsx b/src/components/campaign/demand/DemandForm.tsx
index 4fa508fd..d98d22de 100644
--- a/src/components/campaign/demand/DemandForm.tsx
+++ b/src/components/campaign/demand/DemandForm.tsx
@@ -1,7 +1,8 @@
 'use client'
 
-import { useActionState, useState } from 'react'
+import { useActionState, useCallback, useState } from 'react'
 
+import { AsyncSearchCombobox } from '@/components/campaign/shared/AsyncSearchCombobox'
 import { CampaignFormActionMessage } from '@/components/campaign/shared/CampaignFormActionMessage'
 import type { RelationOption } from '@/components/campaign/shared/RelationMultiSelect'
 import { Button } from '@/components/ui/button'
@@ -11,15 +12,18 @@ import { NativeSelect, NativeSelectOption } from '@/components/ui/native-select'
 import { Spinner } from '@/components/ui/Spinner'
 import { Textarea } from '@/components/ui/textarea'
 import { campaignDemandKindLabels, campaignDemandKinds } from '@/lib/schemas/campaignDemand'
+import type { ActivityRelationOption } from '@/utilities/activityRelationOptions'
 import type { CampaignFormActionState } from '@/utilities/campaignFormActionError'
 import { fieldError } from '@/utilities/campaignFormFields'
-import type { ActivityRelationOption } from '@/utilities/campaignRelationOptions'
 
 type DemandFormProps = {
   municipalityOptions: RelationOption[]
-  activityOptions: ActivityRelationOption[]
+  initialActivity?: ActivityRelationOption | null
   initialMunicipalityId?: number
-  initialActivityId?: number
+  searchActivities: (
+    query: string,
+    municipalityId: number | null,
+  ) => Promise<Array<{ id: number; label: string }>>
   formAction: (
     state: CampaignFormActionState,
     formData: FormData,
@@ -28,19 +32,32 @@ type DemandFormProps = {
 
 export const DemandForm = ({
   municipalityOptions,
-  activityOptions,
+  initialActivity = null,
   initialMunicipalityId,
-  initialActivityId,
+  searchActivities,
   formAction,
 }: DemandFormProps) => {
   const [state, submitAction, isPending] = useActionState(formAction, {})
   const [municipalityId, setMunicipalityId] = useState(
     initialMunicipalityId ? String(initialMunicipalityId) : '',
   )
-  const [activityId, setActivityId] = useState(initialActivityId ? String(initialActivityId) : '')
-  const visibleActivities = municipalityId
-    ? activityOptions.filter((activity) => String(activity.municipalityId) === municipalityId)
-    : activityOptions
+  const [activity, setActivity] = useState<{ id: number; label: string } | null>(
+    initialActivity ? { id: initialActivity.id, label: initialActivity.label } : null,
+  )
+
+  const parsedMunicipalityId = municipalityId ? Number(municipalityId) : null
+  const searchActivitiesForMunicipality = useCallback(
+    (query: string) => searchActivities(query, parsedMunicipalityId),
+    [parsedMunicipalityId, searchActivities],
+  )
+  const activityQueryReady = useCallback(
+    () => parsedMunicipalityId !== null,
+    [parsedMunicipalityId],
+  )
+
+  const activityFieldDescription = parsedMunicipalityId
+    ? 'Opcional. Busque atividades do município selecionado.'
+    : 'Opcional. Escolha o município antes de vincular uma atividade.'
 
   return (
     <form action={submitAction} className="flex max-w-2xl flex-col gap-4">
@@ -82,17 +99,8 @@ export const DemandForm = ({
             required
             value={municipalityId}
             onChange={(event) => {
-              const nextMunicipalityId = event.target.value
-              setMunicipalityId(nextMunicipalityId)
-              const selectedActivity = activityOptions.find(
-                (activity) => String(activity.id) === activityId,
-              )
-              if (
-                selectedActivity &&
-                String(selectedActivity.municipalityId) !== nextMunicipalityId
-              ) {
-                setActivityId('')
-              }
+              setMunicipalityId(event.target.value)
+              setActivity(null)
             }}
             className="min-h-11 w-full"
           >
@@ -112,31 +120,29 @@ export const DemandForm = ({
       </div>
       <Field>
         <FieldLabel htmlFor="demand-activity">Atividade relacionada</FieldLabel>
-        <NativeSelect
-          id="demand-activity"
-          name="activityId"
-          value={activityId}
-          onChange={(event) => {
-            const nextActivityId = event.target.value
-            setActivityId(nextActivityId)
-            const selectedActivity = activityOptions.find(
-              (activity) => String(activity.id) === nextActivityId,
-            )
-            if (selectedActivity) setMunicipalityId(String(selectedActivity.municipalityId))
-          }}
-          className="min-h-11 w-full"
-        >
-          <NativeSelectOption value="">Nenhuma atividade</NativeSelectOption>
-          {visibleActivities.map((option) => (
-            <NativeSelectOption key={option.id} value={String(option.id)}>
-              {option.name}
-            </NativeSelectOption>
-          ))}
-        </NativeSelect>
-        <FieldDescription>
-          Opcional. Ao escolher uma atividade, o município correspondente é preenchido
-          automaticamente.
-        </FieldDescription>
+        {parsedMunicipalityId ? (
+          <AsyncSearchCombobox
+            name="activityId"
+            label="Atividade relacionada"
+            value={activity}
+            emptyOptionLabel="Nenhuma atividade"
+            dialogDescription="Busque atividades do município selecionado por título."
+            isQueryReady={activityQueryReady}
+            queryTooShortMessage="Selecione o município para buscar atividades."
+            search={searchActivitiesForMunicipality}
+            onChange={setActivity}
+          />
+        ) : (
+          <Button
+            type="button"
+            variant="outline"
+            disabled
+            className="min-h-11 w-full justify-between font-normal opacity-70"
+          >
+            Selecione o município primeiro…
+          </Button>
+        )}
+        <FieldDescription>{activityFieldDescription}</FieldDescription>
         {fieldError(state.fieldErrors, 'activity') ? (
           <FieldError>{fieldError(state.fieldErrors, 'activity')}</FieldError>
         ) : null}
diff --git a/src/utilities/activityDetailPageData.ts b/src/utilities/activityDetailPageData.ts
index 2ead3e30..8c874c52 100644
--- a/src/utilities/activityDetailPageData.ts
+++ b/src/utilities/activityDetailPageData.ts
@@ -13,6 +13,8 @@ import {
   type ActivityMunicipalitySummary,
 } from '@/utilities/activityViewModels'
 
+export const ACTIVITY_LINKED_DEMANDS_PAGE_SIZE = 10
+
 type ActivityDemandSummary = {
   id: number
   title: string
@@ -22,6 +24,22 @@ type ActivityDemandSummary = {
   cost: number | null
 }
 
+export type ActivityLinkedDemandsPage = {
+  demands: ActivityDemandSummary[]
+  page: number
+  totalPages: number
+  totalDocs: number
+  demandCostTotal: number
+}
+
+const emptyLinkedDemandsPage = (): ActivityLinkedDemandsPage => ({
+  demands: [],
+  page: 1,
+  totalPages: 1,
+  totalDocs: 0,
+  demandCostTotal: 0,
+})
+
 const loadActivityUpdateAuthorNames = async (
   payload: Pick<Payload, 'find'>,
   user: CampaignUser,
@@ -75,17 +93,63 @@ const loadActivityMunicipalitySummaryById = async (
     : null
 }
 
+const loadLinkedDemandsPage = async (
+  payload: Pick<Payload, 'find'>,
+  user: CampaignUser,
+  activityId: number,
+  page: number,
+): Promise<ActivityLinkedDemandsPage> => {
+  const where = { activity: { equals: activityId } }
+
+  const [pageResult, costRows] = await Promise.all([
+    payload.find({
+      collection: 'campaignDemand',
+      where,
+      depth: 0,
+      limit: ACTIVITY_LINKED_DEMANDS_PAGE_SIZE,
+      page,
+      sort: '-createdAt',
+      select: { title: true, slug: true, kind: true, status: true, cost: true },
+      user,
+      overrideAccess: false,
+    }),
+    payload.find({
+      collection: 'campaignDemand',
+      where,
+      depth: 0,
+      limit: 0,
+      pagination: false,
+      select: { cost: true },
+      user,
+      overrideAccess: false,
+    }),
+  ])
+
+  const demands = pageResult.docs.map((demand) => ({
+    id: demand.id,
+    title: demand.title,
+    slug: demand.slug,
+    kind: demand.kind,
+    status: demand.status,
+    cost: demand.cost ?? null,
+  }))
+
+  return {
+    demands,
+    page: pageResult.page ?? page,
+    totalPages: pageResult.totalPages,
+    totalDocs: pageResult.totalDocs,
+    demandCostTotal: costRows.docs.reduce((total, demand) => total + (demand.cost ?? 0), 0),
+  }
+}
+
 export const getActivityDetailPageData = async (
   payload: Pick<Payload, 'find'>,
   user: CampaignUser,
   context: AccessibleActivityContext,
   activeTab: ActivityDetailTab,
-): Promise<
-  ActivityDetailViewModel & {
-    demands: ActivityDemandSummary[]
-    demandCostTotal: number
-  }
-> => {
+  linkedDemandsPage = 1,
+): Promise<ActivityDetailViewModel & ActivityLinkedDemandsPage> => {
   const municipalityId = relationshipId(context.document.municipality)
   const populatedMunicipalitySummary =
     activityMunicipalitySummary(context.document.municipality) ?? null
@@ -98,39 +162,18 @@ export const getActivityDetailPageData = async (
     activeTab === 'updates' && context.document.updates?.length
       ? loadActivityUpdateAuthorNames(payload, user, context.document.updates)
       : Promise.resolve(new Map<number, string>())
-  const demandSummariesPromise: Promise<ActivityDemandSummary[]> =
+  const linkedDemandsPromise =
     activeTab === 'overview'
-      ? payload
-          .find({
-            collection: 'campaignDemand',
-            where: { activity: { equals: context.id } },
-            depth: 0,
-            pagination: false,
-            sort: 'createdAt',
-            select: { title: true, slug: true, kind: true, status: true, cost: true },
-            user,
-            overrideAccess: false,
-          })
-          .then(({ docs }) =>
-            docs.map((demand) => ({
-              id: demand.id,
-              title: demand.title,
-              slug: demand.slug,
-              kind: demand.kind,
-              status: demand.status,
-              cost: demand.cost ?? null,
-            })),
-          )
-      : Promise.resolve([])
-  const [municipalitySummary, authorNames, demands] = await Promise.all([
+      ? loadLinkedDemandsPage(payload, user, context.id, linkedDemandsPage)
+      : Promise.resolve(emptyLinkedDemandsPage())
+  const [municipalitySummary, authorNames, linkedDemands] = await Promise.all([
     municipalitySummaryPromise,
     authorNamesPromise,
-    demandSummariesPromise,
+    linkedDemandsPromise,
   ])
 
   return {
     ...toActivityDetailViewModel(context.document, activeTab, authorNames, municipalitySummary),
-    demands,
-    demandCostTotal: demands.reduce((total, demand) => total + (demand.cost ?? 0), 0),
+    ...linkedDemands,
   }
 }
diff --git a/src/utilities/activityDetailTabUi.ts b/src/utilities/activityDetailTabUi.ts
index 84ea4443..b7842f19 100644
--- a/src/utilities/activityDetailTabUi.ts
+++ b/src/utilities/activityDetailTabUi.ts
@@ -9,7 +9,7 @@ const helpers = createDetailTabHelpers<ActivityDetailTab>({
   tabs: activityDetailTabs,
   defaultTab: 'overview',
   tabQueryKeys: {
-    overview: [],
+    overview: ['demandsPage'],
     tasks: [],
     updates: ['newUpdate'],
   },
diff --git a/src/utilities/activityRelationOptions.ts b/src/utilities/activityRelationOptions.ts
new file mode 100644
index 00000000..75705486
--- /dev/null
+++ b/src/utilities/activityRelationOptions.ts
@@ -0,0 +1,85 @@
+import 'server-only'
+
+import type { Payload } from 'payload'
+
+import { relationshipId } from '@/lib/relationship'
+import type { CampaignUser } from '@/payload-types'
+
+export type ActivityRelationOption = {
+  id: number
+  label: string
+  municipalityId: number
+}
+
+export const ACTIVITY_RELATION_SEARCH_LIMIT = 20
+
+const MIN_ACTIVITY_TITLE_QUERY_LENGTH = 2
+
+const isActivityTitleQueryReady = (query: string) =>
+  query.trim().length === 0 || query.trim().length >= MIN_ACTIVITY_TITLE_QUERY_LENGTH
+
+const toActivityRelationOption = (activity: {
+  id: number
+  title: string
+  municipality: unknown
+}): ActivityRelationOption | null => {
+  const municipalityId = relationshipId(activity.municipality)
+  if (!municipalityId) return null
+  return { id: activity.id, label: activity.title, municipalityId }
+}
+
+export const loadActivityRelationOptionById = async (
+  payload: Pick<Payload, 'find'>,
+  user: CampaignUser,
+  activityId: number,
+): Promise<ActivityRelationOption | null> => {
+  const result = await payload.find({
+    collection: 'activity',
+    where: { id: { equals: activityId } },
+    depth: 0,
+    limit: 1,
+    pagination: false,
+    select: { title: true, municipality: true },
+    user,
+    overrideAccess: false,
+  })
+
+  const activity = result.docs[0]
+  return activity ? toActivityRelationOption(activity) : null
+}
+
+/**
+ * Server-backed activity picker for demand forms — scoped to one municipality when set.
+ * Empty query returns recent activities in that municipality; typed query filters by title.
+ */
+export const searchActivityRelationOptions = async (
+  payload: Pick<Payload, 'find'>,
+  user: CampaignUser,
+  query: string,
+  municipalityId: number | null,
+): Promise<ActivityRelationOption[]> => {
+  if (!municipalityId || !isActivityTitleQueryReady(query)) return []
+
+  const trimmed = query.trim().slice(0, 120)
+
+  const result = await payload.find({
+    collection: 'activity',
+    where: {
+      and: [
+        { municipality: { equals: municipalityId } },
+        ...(trimmed ? [{ title: { contains: trimmed } }] : []),
+      ],
+    },
+    depth: 0,
+    limit: ACTIVITY_RELATION_SEARCH_LIMIT,
+    page: 1,
+    sort: 'title',
+    select: { title: true, municipality: true },
+    user,
+    overrideAccess: false,
+  })
+
+  return result.docs
+    .map((activity) => toActivityRelationOption(activity))
+    .filter((option): option is ActivityRelationOption => option !== null)
+}
diff --git a/src/utilities/campaignDemandData.ts b/src/utilities/campaignDemandData.ts
index 717af313..d34b04fe 100644
--- a/src/utilities/campaignDemandData.ts
+++ b/src/utilities/campaignDemandData.ts
@@ -38,11 +38,13 @@ export type DemandListState = {
   page: number
   status?: CampaignDemandStatus
   kind?: CampaignDemandKind
+  activityId?: number
 }
 
 export const parseDemandListParams = (searchParams: RawSearchParams): DemandListState => {
   const rawStatus = firstValue(searchParams.status)
   const rawKind = firstValue(searchParams.kind)
+  const activityId = strictDecimalInteger(firstValue(searchParams.activity))
 
   return {
     page: strictDecimalInteger(firstValue(searchParams.page)) ?? 1,
@@ -52,6 +54,7 @@ export const parseDemandListParams = (searchParams: RawSearchParams): DemandList
     ...(campaignDemandKinds.includes(rawKind as CampaignDemandKind)
       ? { kind: rawKind as CampaignDemandKind }
       : {}),
+    ...(activityId ? { activityId } : {}),
   }
 }
 
@@ -62,6 +65,7 @@ const buildDemandListSearchParams = (
   const params = new URLSearchParams()
   if (state.status) params.set('status', state.status)
   if (state.kind) params.set('kind', state.kind)
+  if (state.activityId) params.set('activity', String(state.activityId))
   if (page > 1) params.set('page', String(page))
   return params
 }
@@ -141,6 +145,7 @@ export const loadDemandListPageData = async (
         and: [
           ...(state.status ? [{ status: { equals: state.status } }] : []),
           ...(state.kind ? [{ kind: { equals: state.kind } }] : []),
+          ...(state.activityId ? [{ activity: { equals: state.activityId } }] : []),
         ],
       },
       depth: 0,
diff --git a/src/utilities/campaignRelationOptions.ts b/src/utilities/campaignRelationOptions.ts
index cc77c039..36c81e0f 100644
--- a/src/utilities/campaignRelationOptions.ts
+++ b/src/utilities/campaignRelationOptions.ts
@@ -3,13 +3,9 @@ import 'server-only'
 import type { Payload } from 'payload'
 
 import type { RelationOption } from '@/components/campaign/shared/RelationMultiSelect'
-import { populatedContactName, relationshipId } from '@/lib/relationship'
+import { populatedContactName } from '@/lib/relationship'
 import type { CampaignUser } from '@/payload-types'
 
-export type ActivityRelationOption = RelationOption & {
-  municipalityId: number
-}
-
 /** Municipalities the actor may operate on (coordinator: all 436; advisor: administered). */
 export const loadMunicipalityOptions = async (
   payload: Payload,
@@ -47,28 +43,6 @@ export const loadOrganizationOptions = async (
   return result.docs.map((organization) => ({ id: organization.id, name: organization.name }))
 }
 
-export const loadActivityOptions = async (
-  payload: Payload,
-  user: CampaignUser,
-): Promise<ActivityRelationOption[]> => {
-  const result = await payload.find({
-    collection: 'activity',
-    depth: 0,
-    limit: 0,
-    pagination: false,
-    sort: 'title',
-    select: { title: true, municipality: true },
-    where: {},
-    user,
-    overrideAccess: false,
-  })
-
-  return result.docs.flatMap((activity) => {
-    const municipalityId = relationshipId(activity.municipality)
-    return municipalityId ? [{ id: activity.id, name: activity.title, municipalityId }] : []
-  })
-}
-
 /**
  * `name` folds in the party for select/typeahead disambiguation (e.g.
  * `RelationMultiSelect`); `plainName`/`party`/`slug` ride along so cell-level
diff --git a/tests/e2e/campaignActivity.e2e.spec.ts b/tests/e2e/campaignActivity.e2e.spec.ts
index e8165646..c2ef7c8d 100644
--- a/tests/e2e/campaignActivity.e2e.spec.ts
+++ b/tests/e2e/campaignActivity.e2e.spec.ts
@@ -42,7 +42,8 @@ test.describe('Atividades — registro-fundação', () => {
     await expect(page.getByRole('link', { name: materialDemand })).toBeVisible()
 
     await page.getByRole('link', { name: 'Adicionar demanda' }).click()
-    await expect(page.getByLabel('Atividade relacionada')).toHaveValue(/\d+/)
+    await expect(page.locator('input[name="activityId"]')).toHaveValue(/\d+/)
+    await expect(page.getByLabel('Atividade relacionada')).toContainText(activityTitle)
     await expect(page.getByLabel('Município')).toHaveValue(String(municipality.id))
 
     await page.goto(`${campaign.baseURL}/campanha/municipios/${municipality.slug}?tab=updates`)
diff --git a/tests/unit/activityRelationOptions.unit.spec.ts b/tests/unit/activityRelationOptions.unit.spec.ts
new file mode 100644
index 00000000..6b0577b8
--- /dev/null
+++ b/tests/unit/activityRelationOptions.unit.spec.ts
@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest'
+
+import { ACTIVITY_LINKED_DEMANDS_PAGE_SIZE } from '@/utilities/activityDetailPageData'
+import { ACTIVITY_RELATION_SEARCH_LIMIT } from '@/utilities/activityRelationOptions'
+import { parseDemandListParams } from '@/utilities/campaignDemandData'
+
+describe('activityRelationOptions', () => {
+  it('caps search results at the configured limit', () => {
+    expect(ACTIVITY_RELATION_SEARCH_LIMIT).toBe(20)
+  })
+})
+
+describe('activity linked demands scale (C11)', () => {
+  it('uses a bounded page size for overview cards', () => {
+    expect(ACTIVITY_LINKED_DEMANDS_PAGE_SIZE).toBe(10)
+  })
+
+  it('parses activity filter on the demand list', () => {
+    expect(parseDemandListParams({ activity: '42', page: '2' })).toEqual({
+      page: 2,
+      activityId: 42,
+    })
+  })
+})
diff --git a/tests/unit/codebaseConventions.unit.spec.ts b/tests/unit/codebaseConventions.unit.spec.ts
index fece7ff3..432ccc9a 100644
--- a/tests/unit/codebaseConventions.unit.spec.ts
+++ b/tests/unit/codebaseConventions.unit.spec.ts
@@ -366,6 +366,7 @@ describe('src/utilities top-level is pinned', () => {
     'activityFormData.ts',
     'activityLeadershipOptions.ts',
     'activityPageData.ts',
+    'activityRelationOptions.ts',
     'activityUi.ts',
     'activityViewModels.ts',
     'advisorData.ts',