diff --git a/src/components/campaign/activity/ActivityDateTimeField.tsx b/src/components/campaign/activity/ActivityDateTimeField.tsx
index d954b166..9a3ab854 100644
--- a/src/components/campaign/activity/ActivityDateTimeField.tsx
+++ b/src/components/campaign/activity/ActivityDateTimeField.tsx
@@ -18,6 +18,7 @@ import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/Popover
 import {
   floorToMinuteStep,
   formatBahiaCivilDate,
+  formatBahiaCivilDateLabel,
   formatBahiaCivilDateTimeLabel,
   hourOptions,
   minuteOptionsForStep,
@@ -37,6 +38,9 @@ import { cn } from '@/lib/utils'
  * C103 — on narrow viewports the picker opens as a nested bottom sheet
  * (calendar + hour/minute fully on screen, "Pronto" applies and closes),
  * keeping the desktop popover untouched.
+ *
+ * C104 — `timeVisible={false}` is the all-day mode: the trigger formats only
+ * the date and the picker renders just the calendar (no time selects).
  */
 export const ActivityDateTimeField = ({
   id,
@@ -47,6 +51,7 @@ export const ActivityDateTimeField = ({
   isNarrow = false,
   label,
   required = false,
+  timeVisible = true,
 }: {
   id: string
   value: string
@@ -60,6 +65,8 @@ export const ActivityDateTimeField = ({
   label?: string
   /** Marks the required fields with a visible asterisk on the narrow trigger. */
   required?: boolean
+  /** When false, hide the time selects and label the trigger with the date only. */
+  timeVisible?: boolean
 }) => {
   const [open, setOpen] = useState(false)
   const civil = floorToMinuteStep(value)
@@ -96,7 +103,9 @@ export const ActivityDateTimeField = ({
           'border-destructive ring-3 ring-destructive/20 focus-visible:border-destructive focus-visible:ring-destructive/20',
       )}
     >
-      <span className="truncate">{formatBahiaCivilDateTimeLabel(civil)}</span>
+      <span className="truncate">
+        {timeVisible ? formatBahiaCivilDateTimeLabel(civil) : formatBahiaCivilDateLabel(civil)}
+      </span>
       {isNarrow && required ? (
         <span aria-hidden="true" className="font-semibold text-destructive">
           *
@@ -122,38 +131,40 @@ export const ActivityDateTimeField = ({
           className="w-full p-2"
         />
       ) : null}
-      <div className="flex flex-col gap-3 border-t p-3">
-        <div className="grid grid-cols-2 gap-3">
-          <div className="flex flex-col gap-1">
-            <span className="text-xs font-medium text-muted-foreground select-none">Hora</span>
-            <NativeSelect
-              aria-label="Hora"
-              value={hour}
-              onChange={(event) => setHour(event.target.value)}
-            >
-              {hourOptions.map((option) => (
-                <NativeSelectOption key={option} value={option}>
-                  {option}h
-                </NativeSelectOption>
-              ))}
-            </NativeSelect>
-          </div>
-          <div className="flex flex-col gap-1">
-            <span className="text-xs font-medium text-muted-foreground select-none">Minuto</span>
-            <NativeSelect
-              aria-label="Minuto"
-              value={minute}
-              onChange={(event) => setMinute(event.target.value)}
-            >
-              {minuteOptionsForStep().map((option) => (
-                <NativeSelectOption key={option} value={option}>
-                  {option}
-                </NativeSelectOption>
-              ))}
-            </NativeSelect>
+      {timeVisible ? (
+        <div className="flex flex-col gap-3 border-t p-3">
+          <div className="grid grid-cols-2 gap-3">
+            <div className="flex flex-col gap-1">
+              <span className="text-xs font-medium text-muted-foreground select-none">Hora</span>
+              <NativeSelect
+                aria-label="Hora"
+                value={hour}
+                onChange={(event) => setHour(event.target.value)}
+              >
+                {hourOptions.map((option) => (
+                  <NativeSelectOption key={option} value={option}>
+                    {option}h
+                  </NativeSelectOption>
+                ))}
+              </NativeSelect>
+            </div>
+            <div className="flex flex-col gap-1">
+              <span className="text-xs font-medium text-muted-foreground select-none">Minuto</span>
+              <NativeSelect
+                aria-label="Minuto"
+                value={minute}
+                onChange={(event) => setMinute(event.target.value)}
+              >
+                {minuteOptionsForStep().map((option) => (
+                  <NativeSelectOption key={option} value={option}>
+                    {option}
+                  </NativeSelectOption>
+                ))}
+              </NativeSelect>
+            </div>
           </div>
         </div>
-      </div>
+      ) : null}
     </>
   )
 
diff --git a/src/components/campaign/activity/ActivityInlineCreate.tsx b/src/components/campaign/activity/ActivityInlineCreate.tsx
index 412e7fd8..71029f25 100644
--- a/src/components/campaign/activity/ActivityInlineCreate.tsx
+++ b/src/components/campaign/activity/ActivityInlineCreate.tsx
@@ -13,6 +13,7 @@ import { ResponsibleMultiSelect } from '@/components/campaign/shared/Responsible
 import { StrictCombobox } from '@/components/campaign/shared/StrictCombobox'
 import { Alert, AlertDescription } from '@/components/ui/Alert'
 import { Button } from '@/components/ui/button'
+import { Checkbox } from '@/components/ui/Checkbox'
 import {
   Drawer,
   DrawerContent,
@@ -24,6 +25,7 @@ import { Field, FieldError, FieldLabel } from '@/components/ui/field'
 import { Input } from '@/components/ui/input'
 import { Popover, PopoverAnchor, PopoverContent } from '@/components/ui/Popover'
 import { Spinner } from '@/components/ui/Spinner'
+import { allDayEndInstant, allDayRangeValid, allDayStartInstant } from '@/lib/activityAllDay'
 import {
   formatBahiaDateTimeLabel,
   formatIsoAsBahiaDateTimeInput,
@@ -113,6 +115,8 @@ type InlineDateTimeFieldProps = {
   invalid: boolean
   error?: string
   required?: boolean
+  /** C104 — false hides the time selects (all-day mode). */
+  timeVisible?: boolean
 }
 
 const InlineDateTimeField = ({
@@ -124,6 +128,7 @@ const InlineDateTimeField = ({
   invalid,
   error,
   required = false,
+  timeVisible = true,
 }: InlineDateTimeFieldProps) => (
   <Field data-invalid={invalid}>
     <FieldLabel htmlFor={id} className={sheet ? 'sr-only' : undefined}>
@@ -141,6 +146,7 @@ const InlineDateTimeField = ({
       isNarrow={sheet}
       label={label}
       required={required}
+      timeVisible={timeVisible}
     />
     {error ? <FieldError id={`${id}-error`}>{error}</FieldError> : null}
   </Field>
@@ -167,6 +173,7 @@ const ActivityInlineCreateForm = ({
   const [title, setTitle] = useState('')
   const [start, setStart] = useState(formatIsoAsBahiaDateTimeInput(startAt))
   const [end, setEnd] = useState(formatIsoAsBahiaDateTimeInput(endAt))
+  const [allDay, setAllDay] = useState(false)
   const [locality, setLocality] = useState('')
   const [tags, setTags] = useState<string[]>([])
   const preselectedMunicipalityId =
@@ -181,12 +188,19 @@ const ActivityInlineCreateForm = ({
 
   const errorFor = (name: string) => fieldErrors[name]?.[0]
 
+  const allDayStartDate = start.slice(0, 10)
+  const allDayEndDate = end ? end.slice(0, 10) : allDayStartDate
+
   // C105 — the href mirrors the LIVE state (times edited in the sheet, typed
   // tags), not the slot draft, so "Mais detalhes" carries everything the user
   // actually filled.
   const moreDetailsHref = buildActivityCreateHref(agendaState, {
-    startAt: parseBahiaDateTimeInput(start) ?? undefined,
-    endAt: end ? (parseBahiaDateTimeInput(end) ?? undefined) : undefined,
+    ...(allDay
+      ? { allDay: true, startAt: allDayStartDate, endAt: allDayEndDate }
+      : {
+          startAt: parseBahiaDateTimeInput(start) ?? undefined,
+          endAt: end ? (parseBahiaDateTimeInput(end) ?? undefined) : undefined,
+        }),
     municipalityId: municipalityValue ? Number(municipalityValue) : undefined,
     title: title.trim() || undefined,
     tags: tags.length > 0 ? tags : undefined,
@@ -207,9 +221,17 @@ const ActivityInlineCreateForm = ({
       nextFieldErrors.title = ['Informe um título com ao menos 2 caracteres.']
     }
     if (!municipalityId) nextFieldErrors.municipality = ['Informe o município.']
-    if (!startIso) nextFieldErrors.startAt = ['Informe a data e horário de início do compromisso.']
-    if (startIso && endIso && new Date(endIso) <= new Date(startIso)) {
-      nextFieldErrors.endAt = ['O horário de término deve ser posterior ao de início.']
+    if (allDay) {
+      if (!startIso) nextFieldErrors.startAt = ['Informe a data de início do compromisso.']
+      if (startIso && endIso && !allDayRangeValid(startIso, endIso)) {
+        nextFieldErrors.endAt = ['A data de término deve ser igual ou posterior à de início.']
+      }
+    } else {
+      if (!startIso)
+        nextFieldErrors.startAt = ['Informe a data e horário de início do compromisso.']
+      if (startIso && endIso && new Date(endIso) <= new Date(startIso)) {
+        nextFieldErrors.endAt = ['O horário de término deve ser posterior ao de início.']
+      }
     }
     if (Object.keys(nextFieldErrors).length > 0) {
       setFieldErrors(nextFieldErrors)
@@ -224,8 +246,16 @@ const ActivityInlineCreateForm = ({
       const result = await createActivityInline({
         title: trimmedTitle,
         municipality: municipalityId,
-        startAt: startIso as string,
-        ...(endIso ? { endAt: endIso } : {}),
+        ...(allDay
+          ? {
+              allDay: true,
+              startAt: allDayStartInstant(allDayStartDate),
+              ...(end ? { endAt: allDayEndInstant(allDayEndDate) } : {}),
+            }
+          : {
+              startAt: startIso as string,
+              ...(endIso ? { endAt: endIso } : {}),
+            }),
         ...(locality.trim() ? { locality: locality.trim() } : {}),
         ...(responsible ? { responsible } : {}),
         // C105 — the tags mirror state (every chip mutation fires `onChange`),
@@ -259,6 +289,7 @@ const ActivityInlineCreateForm = ({
         invalid={Boolean(errorFor('startAt'))}
         error={errorFor('startAt')}
         required
+        timeVisible={!allDay}
       />
       <InlineDateTimeField
         sheet={sheet}
@@ -268,6 +299,7 @@ const ActivityInlineCreateForm = ({
         onValueChange={setEnd}
         invalid={Boolean(errorFor('endAt'))}
         error={errorFor('endAt')}
+        timeVisible={!allDay}
       />
     </>
   )
@@ -307,6 +339,21 @@ const ActivityInlineCreateForm = ({
             ) : null}
           </Field>
 
+          {/* C104 — all-day toggle: hides the time part of Início/Término. */}
+          <Field
+            orientation="horizontal"
+            className={
+              sheet ? 'min-h-11 gap-2 rounded-none border-0 px-0' : 'min-h-11 rounded-lg border p-3'
+            }
+          >
+            <Checkbox
+              checked={allDay}
+              onCheckedChange={(next) => setAllDay(Boolean(next))}
+              aria-label="Todo o dia"
+            />
+            <span>Todo o dia</span>
+          </Field>
+
           {sheet ? (
             startEndFields
           ) : (