diff --git a/client/src/components/Trips/TripFormModal.test.tsx b/client/src/components/Trips/TripFormModal.test.tsx
index 25e92f2a9..9e671b26f 100644
--- a/client/src/components/Trips/TripFormModal.test.tsx
+++ b/client/src/components/Trips/TripFormModal.test.tsx
@@ -116,6 +116,16 @@ describe('TripFormModal', () => {
     expect(await screen.findByText('Title is required')).toBeInTheDocument();
   });
 
+  it('FE-COMP-TRIPFORM-009b: typing a title clears the title error (#2604)', async () => {
+    const user = userEvent.setup();
+    render(<TripFormModal {...defaultProps} />);
+    const [submitBtn] = screen.getAllByRole('button', { name: 'Create New Trip' }).slice(-1);
+    await user.click(submitBtn as HTMLElement);
+    expect(await screen.findByText('Title is required')).toBeInTheDocument();
+    await user.type(screen.getByPlaceholderText(/Summer in Japan/i), 'P');
+    expect(screen.queryByText('Title is required')).not.toBeInTheDocument();
+  });
+
   it('FE-COMP-TRIPFORM-010: typing title and submitting calls onSave', async () => {
     const user = userEvent.setup();
     const onSave = vi.fn().mockResolvedValue({ trip: buildTrip({ id: 99 }) });
@@ -416,7 +426,7 @@ describe('TripFormModal', () => {
   // Changing the start of a dated trip must go through the date-shift choice step (#1288).
   const changeStartDate = async (user: ReturnType<typeof userEvent.setup>, iso: string) => {
     await user.click(screen.getAllByRole('button', { name: 'Enter date manually' })[0]);
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: iso } });
     fireEvent.keyDown(input, { key: 'Enter' });
   };
@@ -931,7 +941,7 @@ describe('TripFormModal', () => {
 
     await user.type(screen.getByPlaceholderText(/Summer in Japan/i), 'Open Ended');
     await user.click(screen.getAllByRole('button', { name: 'Enter date manually' })[0]);
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '2026-04-10' } });
     fireEvent.keyDown(input, { key: 'Enter' });
 
@@ -951,12 +961,12 @@ describe('TripFormModal', () => {
     await user.type(screen.getByPlaceholderText(/Summer in Japan/i), 'Backwards');
 
     await user.click(screen.getAllByRole('button', { name: 'Enter date manually' })[1]);
-    const endInput = screen.getByPlaceholderText('DD.MM.YYYY');
+    const endInput = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(endInput, { target: { value: '2026-03-01' } });
     fireEvent.keyDown(endInput, { key: 'Enter' });
 
     await user.click(screen.getAllByRole('button', { name: 'Enter date manually' })[0]);
-    const startInput = screen.getByPlaceholderText('DD.MM.YYYY');
+    const startInput = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(startInput, { target: { value: '2026-01-01' } });
     fireEvent.keyDown(startInput, { key: 'Enter' });
 
@@ -1283,7 +1293,7 @@ describe('TripFormModal', () => {
     render(<TripFormModal {...defaultProps} trip={trip} onSave={onSave} />);
 
     await user.click(screen.getAllByRole('button', { name: 'Enter date manually' })[1]);
-    const endInput = screen.getByPlaceholderText('DD.MM.YYYY');
+    const endInput = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(endInput, { target: { value: '2036-01-01' } });
     fireEvent.keyDown(endInput, { key: 'Enter' });
 
@@ -1326,7 +1336,7 @@ describe('TripFormModal', () => {
   };
   const changeEndDate = async (user: ReturnType<typeof userEvent.setup>, iso: string) => {
     await user.click(screen.getAllByRole('button', { name: 'Enter date manually' })[1]);
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: iso } });
     fireEvent.keyDown(input, { key: 'Enter' });
   };
diff --git a/client/src/components/Trips/TripFormModal.tsx b/client/src/components/Trips/TripFormModal.tsx
index 024f171e3..7e5bd31ce 100644
--- a/client/src/components/Trips/TripFormModal.tsx
+++ b/client/src/components/Trips/TripFormModal.tsx
@@ -223,7 +223,9 @@ export default function TripFormModal({ isOpen, onClose, onSave, trip, onCoverUp
     }
   }
 
-  const update = (field, value) => setFormData(prev => {
+  // An edit answers whatever the last save complained about, so the complaint
+  // goes with it rather than standing over the fixed field until the next save.
+  const update = (field, value) => { setError(''); setFormData(prev => {
     const next = { ...prev, [field]: value }
     if (field === 'start_date' && value) {
       if (!prev.end_date || prev.end_date < value) {
@@ -235,7 +237,7 @@ export default function TripFormModal({ isOpen, onClose, onSave, trip, onCoverUp
       }
     }
     return next
-  })
+  }) }
 
   /* The dashboard's shapes, in the app's own tokens.
      `.trek-dash` deliberately scopes its palette to that page, so none of its
diff --git a/client/src/components/shared/CustomDateTimePicker.test.tsx b/client/src/components/shared/CustomDateTimePicker.test.tsx
index 7b258a6d5..288555cd5 100644
--- a/client/src/components/shared/CustomDateTimePicker.test.tsx
+++ b/client/src/components/shared/CustomDateTimePicker.test.tsx
@@ -104,14 +104,14 @@ describe('CustomDatePicker', () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    expect(screen.getByPlaceholderText('DD.MM.YYYY')).toBeTruthy();
+    expect(screen.getByRole('textbox', { name: 'Enter date manually' })).toBeTruthy();
   });
 
   it('FE-COMP-DATEPICKER-012: text input accepts ISO format YYYY-MM-DD', async () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '2026-07-04' } });
     fireEvent.keyDown(input, { key: 'Enter' });
     expect(onChange).toHaveBeenCalledWith('2026-07-04');
@@ -121,7 +121,7 @@ describe('CustomDatePicker', () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '17.07.2026' } });
     fireEvent.keyDown(input, { key: 'Enter' });
     expect(onChange).toHaveBeenCalledWith('2026-07-17');
@@ -131,7 +131,7 @@ describe('CustomDatePicker', () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '31.02.2026' } });
     fireEvent.keyDown(input, { key: 'Enter' });
     expect(onChange).not.toHaveBeenCalled();
@@ -141,7 +141,7 @@ describe('CustomDatePicker', () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '29.02.2024' } });
     fireEvent.keyDown(input, { key: 'Enter' });
     expect(onChange).toHaveBeenCalledWith('2024-02-29');
@@ -151,9 +151,9 @@ describe('CustomDatePicker', () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.keyDown(input, { key: 'Escape' });
-    expect(screen.queryByPlaceholderText('DD.MM.YYYY')).toBeNull();
+    expect(screen.queryByRole('textbox', { name: 'Enter date manually' })).toBeNull();
     expect(screen.getAllByRole('button').length).toBeGreaterThan(0);
   });
 
@@ -183,7 +183,7 @@ describe('CustomDatePicker', () => {
     const user = userEvent.setup();
     render(<CustomDatePicker value="" onChange={onChange} min="2026-03-10" max="2026-03-20" />);
     await user.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '2026-03-25' } });
     fireEvent.keyDown(input, { key: 'Enter' });
     expect(onChange).not.toHaveBeenCalled();
@@ -503,22 +503,22 @@ describe('CustomDatePicker branches', () => {
     openCalendar();
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
 
-    expect(screen.getByPlaceholderText('DD.MM.YYYY')).toHaveProperty('value', '');
+    expect(screen.getByRole('textbox', { name: 'Enter date manually' })).toHaveProperty('value', '');
   });
 
   it('FE-W5DP-010: submitting an empty manual entry does nothing', () => {
     render(<CustomDatePicker value="" onChange={onChange} />);
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
-    fireEvent.blur(screen.getByPlaceholderText('DD.MM.YYYY'));
+    fireEvent.blur(screen.getByRole('textbox', { name: 'Enter date manually' }));
 
     expect(onChange).not.toHaveBeenCalled();
-    expect(screen.queryByPlaceholderText('DD.MM.YYYY')).not.toBeInTheDocument();
+    expect(screen.queryByRole('textbox', { name: 'Enter date manually' })).not.toBeInTheDocument();
   });
 
   it('FE-W5DP-011: a manual entry without three number groups is ignored', () => {
     render(<CustomDatePicker value="" onChange={onChange} />);
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '17.07' } });
     fireEvent.keyDown(input, { key: 'Enter' });
 
@@ -528,7 +528,7 @@ describe('CustomDatePicker branches', () => {
   it('FE-W5DP-012: a manual entry already in locale order is taken as typed', () => {
     render(<CustomDatePicker value="" onChange={onChange} />);
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '07/17/2026' } });
     fireEvent.keyDown(input, { key: 'Enter' });
 
@@ -538,7 +538,7 @@ describe('CustomDatePicker branches', () => {
   it('FE-W5DP-013: a two-digit year is expanded into the 2000s', () => {
     render(<CustomDatePicker value="" onChange={onChange} />);
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '07/17/26' } });
     fireEvent.keyDown(input, { key: 'Enter' });
 
@@ -548,7 +548,7 @@ describe('CustomDatePicker branches', () => {
   it('FE-W5DP-014: an impossible day/month combination is rejected', () => {
     render(<CustomDatePicker value="" onChange={onChange} />);
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '13/45/2026' } });
     fireEvent.keyDown(input, { key: 'Enter' });
 
@@ -558,7 +558,7 @@ describe('CustomDatePicker branches', () => {
   it('FE-W5DP-015: a localised manual entry outside [min,max] is rejected', () => {
     render(<CustomDatePicker value="" onChange={onChange} min="2026-03-10" max="2026-03-20" />);
     fireEvent.click(screen.getByRole('button', { name: /enter date manually/i }));
-    const input = screen.getByPlaceholderText('DD.MM.YYYY');
+    const input = screen.getByRole('textbox', { name: 'Enter date manually' });
     fireEvent.change(input, { target: { value: '03/25/2026' } });
     fireEvent.keyDown(input, { key: 'Enter' });
 
@@ -743,7 +743,7 @@ describe('CustomDatePicker branches', () => {
 
     fireEvent.click(keyboard);
     expect(screen.queryByRole('dialog')).not.toBeInTheDocument();
-    expect(screen.getByPlaceholderText('DD.MM.YYYY')).toHaveProperty('value', '03/15/2026');
+    expect(screen.getByRole('textbox', { name: 'Enter date manually' })).toHaveProperty('value', '03/15/2026');
   });
 });
 
diff --git a/client/src/components/shared/CustomDateTimePicker.tsx b/client/src/components/shared/CustomDateTimePicker.tsx
index 03997564b..f218d9a90 100644
--- a/client/src/components/shared/CustomDateTimePicker.tsx
+++ b/client/src/components/shared/CustomDateTimePicker.tsx
@@ -3,6 +3,7 @@ import { localIsoDate } from '../../utils/localDate';
 import React, { useEffect, useRef, useState } from 'react';
 import { createPortal } from 'react-dom';
 import { useTranslation } from '../../i18n';
+import { dateInputPattern } from '../../utils/dateInputPattern';
 import { useRemeasureSignal } from '../../hooks/useAnchoredPosition';
 import { useWeekStartDay } from '../../hooks/useWeekStartDay';
 import { leadingBlanks, weekdayLabels } from '../../utils/calendarWeek';
@@ -276,8 +277,8 @@ export function CustomDatePicker({
             if (e.key === 'Escape') setIsTyping(false);
           }}
           onBlur={handleTextSubmit}
-          placeholder="DD.MM.YYYY"
-          aria-label="Enter date manually"
+          placeholder={dateInputPattern(locale)}
+          aria-label={t('common.datepicker.enterManually')}
           style={{
             width: '100%',
             padding: '8px 14px',
diff --git a/client/src/mobile/screens/dashboard/MNewTripSheet.tsx b/client/src/mobile/screens/dashboard/MNewTripSheet.tsx
index ce8d4fb5d..d0e4b93dd 100644
--- a/client/src/mobile/screens/dashboard/MNewTripSheet.tsx
+++ b/client/src/mobile/screens/dashboard/MNewTripSheet.tsx
@@ -76,8 +76,10 @@ export default function MNewTripSheet({ open, trip, onClose, onSave, onCoverUpda
     setPendingRemoval(null)
   }, [trip, open])
 
-  // Moving the start keeps the trip length (same rule as TripFormModal).
+  // Moving the start keeps the trip length (same rule as TripFormModal). Every
+  // edit clears the last save's complaint, as on the desktop form.
   const changeStart = (value: string) => {
+    setError('')
     setEndDate(endDateForNewStart(startDate, endDate, value))
     setStartDate(value)
   }
@@ -154,7 +156,7 @@ export default function MNewTripSheet({ open, trip, onClose, onSave, onCoverUpda
           <FieldLabel>{t('dashboard.tripTitle')}</FieldLabel>
           <input
             value={title}
-            onChange={e => canEditTrip && setTitle(e.target.value)}
+            onChange={e => { if (canEditTrip) { setError(''); setTitle(e.target.value) } }}
             readOnly={!canEditTrip}
             placeholder={t('dashboard.tripTitlePlaceholder')}
             className={inputCls}
@@ -165,7 +167,7 @@ export default function MNewTripSheet({ open, trip, onClose, onSave, onCoverUpda
           <FieldLabel>{t('dashboard.tripDescription')}</FieldLabel>
           <textarea
             value={description}
-            onChange={e => canEditTrip && setDescription(e.target.value)}
+            onChange={e => { if (canEditTrip) { setError(''); setDescription(e.target.value) } }}
             readOnly={!canEditTrip}
             placeholder={t('dashboard.tripDescriptionPlaceholder')}
             rows={2}
@@ -188,7 +190,7 @@ export default function MNewTripSheet({ open, trip, onClose, onSave, onCoverUpda
             <FieldLabel>{t('dashboard.endDate')}</FieldLabel>
             <CustomDatePicker
               value={endDate}
-              onChange={v => { if (canEditTrip) setEndDate(v) }}
+              onChange={v => { if (canEditTrip) { setError(''); setEndDate(v) } }}
               placeholder={t('dashboard.endDate')}
               borderless
               style={{ marginTop: 3 }}
@@ -203,7 +205,7 @@ export default function MNewTripSheet({ open, trip, onClose, onSave, onCoverUpda
           <FieldLabel>{t('dashboard.currency')}</FieldLabel>
           <CustomSelect
             value={currency}
-            onChange={v => { if (canEditTrip) setCurrency(String(v)) }}
+            onChange={v => { if (canEditTrip) { setError(''); setCurrency(String(v)) } }}
             disabled={!canEditTrip}
             searchable
             size="sm"
diff --git a/client/src/utils/dateInputPattern.test.ts b/client/src/utils/dateInputPattern.test.ts
new file mode 100644
index 000000000..9921b8020
--- /dev/null
+++ b/client/src/utils/dateInputPattern.test.ts
@@ -0,0 +1,18 @@
+import { describe, expect, it } from 'vitest';
+import { dateInputPattern } from './dateInputPattern';
+
+// The manual date field's hint has to read the way the field is filled and
+// parsed in the user's language; it used to say DD.MM.YYYY everywhere (#2604).
+describe('dateInputPattern', () => {
+  it('follows the field order and separators of the locale', () => {
+    expect(dateInputPattern('de-DE')).toBe('DD.MM.YYYY');
+    expect(dateInputPattern('en-US')).toBe('MM/DD/YYYY');
+    expect(dateInputPattern('en-GB')).toBe('DD/MM/YYYY');
+    expect(dateInputPattern('ko-KR')).toBe('YYYY. MM. DD.');
+  });
+
+  it('takes the shape only, never the locale digits', () => {
+    expect(dateInputPattern('ar')).not.toMatch(/[٠-٩\d]/);
+    expect(dateInputPattern('ar')).toContain('YYYY');
+  });
+});
diff --git a/client/src/utils/dateInputPattern.ts b/client/src/utils/dateInputPattern.ts
new file mode 100644
index 000000000..ddc2ee590
--- /dev/null
+++ b/client/src/utils/dateInputPattern.ts
@@ -0,0 +1,15 @@
+const LETTERS: Record<string, string> = { day: 'DD', month: 'MM', year: 'YYYY' };
+
+/**
+ * How a typed date is written in `locale`, as letters (DD, MM, YYYY) between the
+ * locale's own separators. It is the hint of the manual date field, which is
+ * pre-filled and read back in this same order, so a Korean user sees
+ * "YYYY. MM. DD." rather than a German "DD.MM.YYYY". Direction marks are dropped:
+ * the hint shows the shape, the field itself carries the script.
+ */
+export function dateInputPattern(locale: string): string {
+  return new Intl.DateTimeFormat(locale, { day: '2-digit', month: '2-digit', year: 'numeric', timeZone: 'UTC' })
+    .formatToParts(new Date(Date.UTC(2001, 5, 15)))
+    .map((part) => LETTERS[part.type] ?? part.value.replace(/[؜‎‏]/g, ''))
+    .join('');
+}
diff --git a/client/tests/unit/mobile/dashboard/MNewTripSheet.test.tsx b/client/tests/unit/mobile/dashboard/MNewTripSheet.test.tsx
index 88a573bf0..d4846cab4 100644
--- a/client/tests/unit/mobile/dashboard/MNewTripSheet.test.tsx
+++ b/client/tests/unit/mobile/dashboard/MNewTripSheet.test.tsx
@@ -124,6 +124,16 @@ describe('MNewTripSheet', () => {
     expect(onSave).not.toHaveBeenCalled();
   });
 
+  it('FE-MOB-NTSH-003b: typing a title clears the title error (#2604)', () => {
+    render(<MNewTripSheet open trip={null} onClose={() => {}} onSave={vi.fn(async () => undefined)} />)
+
+    fireEvent.click(screen.getByRole('button', { name: 'Create New Trip' }))
+    expect(screen.getByText('Title is required')).toBeInTheDocument()
+
+    fireEvent.change(screen.getByPlaceholderText('e.g. Summer in Japan'), { target: { value: 'P' } })
+    expect(screen.queryByText('Title is required')).not.toBeInTheDocument()
+  })
+
   it('FE-MOB-NTSH-004: an end date before the start blocks the save', () => {
     const onSave = vi.fn(async () => undefined);
     render(<MNewTripSheet open trip={null} onClose={() => {}} onSave={onSave} />);