diff --git a/client/src/components/Planner/ReservationModal.test.tsx b/client/src/components/Planner/ReservationModal.test.tsx
index dd7a549b8..8258f2d42 100644
--- a/client/src/components/Planner/ReservationModal.test.tsx
+++ b/client/src/components/Planner/ReservationModal.test.tsx
@@ -1,4 +1,4 @@
-// FE-PLANNER-RESMODAL-001 to FE-PLANNER-RESMODAL-080
+// FE-PLANNER-RESMODAL-001 to FE-PLANNER-RESMODAL-093
 import { render, screen, waitFor, fireEvent, within } from '../../../tests/helpers/render';
 import userEvent from '@testing-library/user-event';
 import { http, HttpResponse } from 'msw';
@@ -1437,6 +1437,96 @@ describe('ReservationModal', () => {
     expect(times.map(i => i.value)).toEqual(['', '', '']);
   });
 
+  // #2107 — a booking that lasts a whole day has no clock to compare, and filling the
+  // missing one with midnight made the comparison read as inverted.
+  it('FE-PLANNER-RESMODAL-089: the same start and end date with no times is accepted', async () => {
+    const onSave = vi.fn().mockResolvedValue(undefined);
+    render(<ReservationModal {...defaultProps} onSave={onSave} days={reviewDays()} />);
+
+    await userEvent.type(screen.getByPlaceholderText(/e\.g\. Lufthansa/i), 'Park permit');
+    const datePickers = screen.getAllByTestId('date-picker');
+    fireEvent.change(datePickers[0], { target: { value: '2026-05-02' } });
+    fireEvent.change(datePickers[1], { target: { value: '2026-05-02' } });
+
+    expect(screen.queryByText(/End date\/time must be after start/i)).toBeNull();
+    fireEvent.submit(document.querySelector('form')!);
+    await waitFor(() => expect(onSave).toHaveBeenCalled());
+  });
+
+  it('FE-PLANNER-RESMODAL-090: an all-day booking is saved as bare dates on both ends', async () => {
+    const onSave = vi.fn().mockResolvedValue(undefined);
+    render(<ReservationModal {...defaultProps} onSave={onSave} days={reviewDays()} />);
+
+    await userEvent.type(screen.getByPlaceholderText(/e\.g\. Lufthansa/i), 'Park permit');
+    const datePickers = screen.getAllByTestId('date-picker');
+    fireEvent.change(datePickers[0], { target: { value: '2026-05-02' } });
+    fireEvent.change(datePickers[1], { target: { value: '2026-05-02' } });
+    fireEvent.submit(document.querySelector('form')!);
+
+    // The stored shape matters: the calendar export branches on whether the value
+    // carries a clock, and a bare date is what makes it an all-day event.
+    await waitFor(() => expect(onSave).toHaveBeenCalledWith(
+      expect.objectContaining({ reservation_time: '2026-05-02', reservation_end_time: '2026-05-02' }),
+    ));
+  });
+
+  it('FE-PLANNER-RESMODAL-091: an end date before the start is still refused without times', async () => {
+    const onSave = vi.fn().mockResolvedValue(undefined);
+    const addToast = vi.fn();
+    window.__addToast = addToast;
+    render(<ReservationModal {...defaultProps} onSave={onSave} days={reviewDays()} />);
+
+    await userEvent.type(screen.getByPlaceholderText(/e\.g\. Lufthansa/i), 'Backwards');
+    const datePickers = screen.getAllByTestId('date-picker');
+    fireEvent.change(datePickers[0], { target: { value: '2026-05-02' } });
+    fireEvent.change(datePickers[1], { target: { value: '2026-05-01' } });
+    fireEvent.submit(document.querySelector('form')!);
+
+    expect(onSave).not.toHaveBeenCalled();
+    expect(addToast).toHaveBeenCalledWith(expect.stringMatching(/End date\/time must be after start/i), 'error', undefined);
+    delete window.__addToast;
+  });
+
+  it('FE-PLANNER-RESMODAL-092: a stored booking whose end is a bare date on the start day stays editable', async () => {
+    const onSave = vi.fn().mockResolvedValue(undefined);
+    // The shape the booking import and the mobile sheet both write. Nothing is typed
+    // here: the row alone used to leave the save button dead.
+    const res = buildReservation({
+      id: 21, type: 'event', title: 'Day permit',
+      reservation_time: '2026-05-02T10:00:00', reservation_end_time: '2026-05-02',
+    });
+    render(<ReservationModal {...defaultProps} reservation={res} onSave={onSave} days={reviewDays()} />);
+
+    expect(screen.queryByText(/End date\/time must be after start/i)).toBeNull();
+    fireEvent.submit(document.querySelector('form')!);
+    await waitFor(() => expect(onSave).toHaveBeenCalled());
+  });
+
+  it('FE-PLANNER-RESMODAL-093: switching to hotel clears a date error the hidden panel cannot explain', async () => {
+    render(<ReservationModal {...defaultProps} days={reviewDays()} />);
+
+    await userEvent.type(screen.getByPlaceholderText(/e\.g\. Lufthansa/i), 'Switched');
+    const datePickers = screen.getAllByTestId('date-picker');
+    const timePickers = screen.getAllByTestId('time-picker');
+    fireEvent.change(datePickers[0], { target: { value: '2026-05-02' } });
+    fireEvent.change(timePickers[0], { target: { value: '19:00' } });
+    fireEvent.change(datePickers[1], { target: { value: '2026-05-01' } });
+    expect(screen.getByText(/End date\/time must be after start/i)).toBeTruthy();
+    // The footer button reads 'Add' while creating and 'Update' while editing.
+    const save = () => Array.from(document.querySelectorAll('button'))
+      .find(b => /^\s*(Add|Update)\s*$/.test(b.textContent || '')) as HTMLButtonElement;
+    expect(save().disabled).toBe(true);
+
+    // The date panel is hidden for hotels, and the message sits inside it, so
+    // asserting on the message proves nothing here. The save button is the part
+    // that stayed dead with no visible reason.
+    // The hotel type is labelled 'Accommodation' in the picker.
+    const hotelBtn = Array.from(document.querySelectorAll('button'))
+      .find(b => /^\s*Accommodation\s*$/.test(b.textContent || ''))!;
+    fireEvent.click(hotelBtn);
+    expect(save().disabled).toBe(false);
+  });
+
   it('FE-PLANNER-RESMODAL-088: double-encoded metadata still fills the check-in times', () => {
     const res = buildReservation({ id: 18, title: 'Grand Hotel', type: 'hotel' });
     (res as unknown as { metadata: string }).metadata =
diff --git a/client/src/components/Planner/ReservationModal.tsx b/client/src/components/Planner/ReservationModal.tsx
index 4b550e6e1..167ba7b0b 100644
--- a/client/src/components/Planner/ReservationModal.tsx
+++ b/client/src/components/Planner/ReservationModal.tsx
@@ -224,14 +224,25 @@ export function ReservationModal({ isOpen, onClose, onSave, reservation, days, p
     return next
   })
 
+  // Mirrors the mobile sheet, which has had this shape since 72a82b3c while the
+  // desktop copy was never pulled across (#2107). Filling a missing clock with '00:00' made a
+  // day-long booking compare as midnight against midnight, and the comparison is
+  // strict, so an all-day permit on a single date was refused. It also left every
+  // booking with a date-only end time uneditable here, which is the shape the booking
+  // import and the mobile sheet both write.
+  //
+  // The hotel guard matters for the same reason it does on mobile: the date panel is
+  // hidden for hotels, so a type switch after typing dates would leave the save button
+  // dead with its explanation inside the hidden block.
   const isEndBeforeStart = (() => {
-    if (!form.end_date || !form.reservation_time) return false
+    if (form.type === 'hotel' || !form.end_date || !form.reservation_time) return false
     const startDate = form.reservation_time.split('T')[0]
-    const startTime = form.reservation_time.split('T')[1] || '00:00'
-    const endTime = form.reservation_end_time || '00:00'
-    const startFull = `${startDate}T${startTime}`
-    const endFull = `${form.end_date}T${endTime}`
-    return endFull <= startFull
+    const startTime = form.reservation_time.split('T')[1] || ''
+    const endTime = form.reservation_end_time || ''
+    // Without a time on either side the booking is all-day, so an end on the
+    // start day is fine — only compare the dates there.
+    if (!startTime || !endTime) return form.end_date < startDate
+    return `${form.end_date}T${endTime}` <= `${startDate}T${startTime}`
   })()
 
   const handleSubmit = async (e?: { preventDefault?: () => void }) => {