diff --git a/frontend/src/pages/ActivityPage.jsx b/frontend/src/pages/ActivityPage.jsx
index ec68925..50ea792 100644
--- a/frontend/src/pages/ActivityPage.jsx
+++ b/frontend/src/pages/ActivityPage.jsx
@@ -38,6 +38,29 @@ function dedupeActivitiesById(rows) {
   return [...m.values()].sort(compareActivities)
 }
 
+/** activity_log: Spalten start_time / end_time sind TIME (Uhrzeit zum Kalendertag date), nicht volles Timestamp. */
+function timeInputValueFromApi(t) {
+  if (t == null || t === '') return ''
+  const s = String(t)
+  if (s.includes('T') && s.length >= 16) return s.slice(11, 16)
+  const m = s.match(/^(\d{1,2}):(\d{2})/)
+  if (!m) return ''
+  return `${m[1].padStart(2, '0')}:${m[2]}`
+}
+
+function timePayloadFromInput(v) {
+  const s = v == null ? '' : String(v).trim()
+  if (!s) return null
+  if (/^\d{2}:\d{2}$/.test(s)) return `${s}:00`
+  if (/^\d{2}:\d{2}:\d{2}$/.test(s)) return s
+  return s
+}
+
+function formatTimeForList(t) {
+  const v = timeInputValueFromApi(t)
+  return v || ''
+}
+
 const ACTIVITY_TYPES = [
   'Traditionelles Krafttraining','Matrial Arts','Outdoor Spaziergang',
   'Innenräume Spaziergang','Laufen','Radfahren','Schwimmen',
@@ -76,6 +99,8 @@ const ACTIVITY_LOG_PAYLOAD_KEYS = new Set([
 function empty() {
   return {
     date: dayjs().format('YYYY-MM-DD'),
+    start_time: '',
+    end_time: '',
     activity_type: 'Traditionelles Krafttraining',
     duration_min: '', kcal_active: '',
     hr_avg: '', hr_max: '', rpe: '', notes: '',
@@ -282,6 +307,30 @@ function EntryForm({
         <input type="date" className="form-input" style={{width:140}} value={form.date} onChange={e=>set('date',e.target.value)}/>
         <span className="form-unit"/>
       </div>
+      <div className="form-row">
+        <label className="form-label">Start (Uhrzeit)</label>
+        <input
+          type="time"
+          step={1}
+          className="form-input"
+          style={{ width: 'auto', minWidth: 140 }}
+          value={timeInputValueFromApi(form.start_time)}
+          onChange={(e) => set('start_time', e.target.value ? timePayloadFromInput(e.target.value) || '' : '')}
+        />
+        <span className="form-unit">zum Datum oben</span>
+      </div>
+      <div className="form-row">
+        <label className="form-label">Ende (Uhrzeit)</label>
+        <input
+          type="time"
+          step={1}
+          className="form-input"
+          style={{ width: 'auto', minWidth: 140 }}
+          value={timeInputValueFromApi(form.end_time)}
+          onChange={(e) => set('end_time', e.target.value ? timePayloadFromInput(e.target.value) || '' : '')}
+        />
+        <span className="form-unit">optional</span>
+      </div>
       <div style={{marginBottom:12}}>
         <TrainingTypeSelect
           value={form.training_type_id}
@@ -502,6 +551,14 @@ export default function ActivityPage() {
     setError(null)
     try {
       const payload = {...form}
+      payload.start_time =
+        payload.start_time === '' || payload.start_time == null
+          ? null
+          : timePayloadFromInput(payload.start_time)
+      payload.end_time =
+        payload.end_time === '' || payload.end_time == null
+          ? null
+          : timePayloadFromInput(payload.end_time)
       if(payload.duration_min) payload.duration_min = parseFloat(payload.duration_min)
       if(payload.kcal_active)  payload.kcal_active  = parseFloat(payload.kcal_active)
       if(payload.hr_avg)       payload.hr_avg       = parseFloat(payload.hr_avg)
@@ -557,6 +614,14 @@ export default function ActivityPage() {
       if (payload.hr_avg !== '' && payload.hr_avg != null) payload.hr_avg = parseFloat(payload.hr_avg)
       if (payload.hr_max !== '' && payload.hr_max != null) payload.hr_max = parseFloat(payload.hr_max)
       if (payload.rpe !== '' && payload.rpe != null) payload.rpe = parseInt(payload.rpe, 10)
+      payload.start_time =
+        payload.start_time === '' || payload.start_time == null
+          ? null
+          : timePayloadFromInput(payload.start_time)
+      payload.end_time =
+        payload.end_time === '' || payload.end_time == null
+          ? null
+          : timePayloadFromInput(payload.end_time)
       await api.updateActivity(editing.id, payload)
       if (sessionDetail?.schema?.length > 0) {
         const metrics = buildMetricsPayload(sessionDetail.schema, metricDraft)
@@ -837,7 +902,12 @@ export default function ActivityPage() {
                         </div>
                         <div style={{fontSize:11,color:'var(--text3)',marginBottom:4}}>
                           {dayjs(e.date).format('dd, DD. MMMM YYYY')}
-                          {e.start_time && e.start_time.length>10 && ` · ${e.start_time.slice(11,16)}`}
+                          {(formatTimeForList(e.start_time) || formatTimeForList(e.end_time)) && (
+                            <span>
+                              {formatTimeForList(e.start_time) && ` · Start ${formatTimeForList(e.start_time)}`}
+                              {formatTimeForList(e.end_time) && ` · Ende ${formatTimeForList(e.end_time)}`}
+                            </span>
+                          )}
                         </div>
                         <div style={{display:'flex',gap:10,flexWrap:'wrap'}}>
                           {e.duration_min && <span style={{fontSize:12,color:'var(--text2)'}}>⏱ {Math.round(e.duration_min)} Min</span>}