diff --git a/client/src/components/Planner/PlaceContactFields.test.tsx b/client/src/components/Planner/PlaceContactFields.test.tsx
index 8b0a6f2f0..7e1213873 100644
--- a/client/src/components/Planner/PlaceContactFields.test.tsx
+++ b/client/src/components/Planner/PlaceContactFields.test.tsx
@@ -73,5 +73,19 @@ describe('PlaceContactFields (#2472)', () => {
     await user.click(screen.getByRole('button', { name: 'Take over from the place details' }))
     expect(JSON.parse(onChange.mock.lastCall![1])).toEqual(looked)
   })
+
+  it('FE-PLANNER-CONTACT-005: the place\'s phone and e-mail keep password managers out', () => {
+    render(<Harness onChange={vi.fn()} />)
+    // A place's address is not the user's login; 1Password filled it in (5.0.0-pre.1 feedback).
+    for (const label of ['Phone', 'E-mail']) {
+      const field = screen.getByLabelText(label)
+      expect(field).toHaveAttribute('data-1p-ignore', 'true')
+      expect(field).toHaveAttribute('data-lpignore', 'true')
+      expect(field).toHaveAttribute('data-bwignore', 'true')
+      expect(field).toHaveAttribute('autocomplete', 'off')
+    }
+    // Still an e-mail field, so the keyboard and the browser's check stay.
+    expect(screen.getByLabelText('E-mail')).toHaveAttribute('type', 'email')
+  })
 })
 
diff --git a/client/src/components/Planner/PlaceContactFields.tsx b/client/src/components/Planner/PlaceContactFields.tsx
index aea631b5a..33be74c8b 100644
--- a/client/src/components/Planner/PlaceContactFields.tsx
+++ b/client/src/components/Planner/PlaceContactFields.tsx
@@ -7,6 +7,7 @@ import { DialogSection, fs } from '../shared/DialogShell'
 import { AddRowButton, EditorField, GRID_2, INPUT } from '../shared/dialogParts'
 import { cleanWeek, readWeek, weekdayNames, writeWeek } from './placeHours'
 import { useTranslation } from '../../i18n'
+import { NO_AUTOFILL } from '../../utils/noAutofill'
 
 interface Props {
   /** Anchor for the "add by hand" jump from an empty search. */
@@ -80,14 +81,14 @@ export function PlaceContactFields({ id: anchorId, phone, email, openingHours, o
           <div className="relative">
             <Phone size={13} strokeWidth={2} className="pointer-events-none absolute start-3 top-1/2 -translate-y-1/2 text-content-faint" />
             <input id={`${id}-phone`} type="tel" value={phone} onChange={e => onChange('phone', e.target.value)}
-              maxLength={50} placeholder="+49 …" className={`${INPUT} ps-8`} />
+              maxLength={50} placeholder="+49 …" className={`${INPUT} ps-8`} {...NO_AUTOFILL} />
           </div>
         </EditorField>
         <EditorField label={t('places.formEmail')} htmlFor={`${id}-email`}>
           <div className="relative">
             <Mail size={13} strokeWidth={2} className="pointer-events-none absolute start-3 top-1/2 -translate-y-1/2 text-content-faint" />
             <input id={`${id}-email`} type="email" value={email} onChange={e => onChange('email', e.target.value)}
-              maxLength={254} placeholder="info@…" className={`${INPUT} ps-8`} />
+              maxLength={254} placeholder="info@…" className={`${INPUT} ps-8`} {...NO_AUTOFILL} />
           </div>
         </EditorField>
       </div>
diff --git a/client/src/mobile/screens/admin/MAdminSheets.tsx b/client/src/mobile/screens/admin/MAdminSheets.tsx
index dc48e1d71..4092cfec0 100644
--- a/client/src/mobile/screens/admin/MAdminSheets.tsx
+++ b/client/src/mobile/screens/admin/MAdminSheets.tsx
@@ -6,6 +6,7 @@ import type { useAdmin } from '../../../pages/admin/useAdmin'
 import MSheet from '../../components/MSheet'
 import MSegmented from '../../components/MSegmented'
 import { MAdminButton, MAdminField, MAdminInput, MAdminSecretInput, MAdminSheetFrame } from './MAdminUi'
+import { NO_AUTOFILL } from '../../../utils/noAutofill'
 
 interface MAdminSheetsProps {
   admin: ReturnType<typeof useAdmin>
@@ -78,6 +79,7 @@ export default function MAdminSheets({ admin, t }: MAdminSheetsProps) {
                 value={createForm.username}
                 onChange={(e) => setCreateForm((f) => ({ ...f, username: e.target.value }))}
                 placeholder={t('settings.username')}
+                {...NO_AUTOFILL}
               />
             </MAdminField>
             <MAdminField label={`${t('common.email')} *`}>
@@ -86,6 +88,7 @@ export default function MAdminSheets({ admin, t }: MAdminSheetsProps) {
                 value={createForm.email}
                 onChange={(e) => setCreateForm((f) => ({ ...f, email: e.target.value }))}
                 placeholder={t('common.email')}
+                {...NO_AUTOFILL}
               />
             </MAdminField>
             <MAdminField label={`${t('common.password')} *`}>
@@ -93,6 +96,7 @@ export default function MAdminSheets({ admin, t }: MAdminSheetsProps) {
                 value={createForm.password}
                 onChange={(e) => setCreateForm((f) => ({ ...f, password: e.target.value }))}
                 placeholder={t('common.password')}
+                autoComplete="new-password"
               />
             </MAdminField>
             <MAdminField label={t('settings.role')}>
@@ -127,6 +131,7 @@ export default function MAdminSheets({ admin, t }: MAdminSheetsProps) {
                   type="text"
                   value={editForm.username}
                   onChange={(e) => setEditForm((f) => ({ ...f, username: e.target.value }))}
+                  {...NO_AUTOFILL}
                 />
               </MAdminField>
               <MAdminField label={t('common.email')}>
@@ -134,6 +139,7 @@ export default function MAdminSheets({ admin, t }: MAdminSheetsProps) {
                   type="email"
                   value={editForm.email}
                   onChange={(e) => setEditForm((f) => ({ ...f, email: e.target.value }))}
+                  {...NO_AUTOFILL}
                 />
               </MAdminField>
               <MAdminField label={t('admin.newPassword')} hint={t('admin.newPasswordHint')}>
@@ -141,6 +147,7 @@ export default function MAdminSheets({ admin, t }: MAdminSheetsProps) {
                   value={editForm.password}
                   onChange={(e) => setEditForm((f) => ({ ...f, password: e.target.value }))}
                   placeholder={t('admin.newPasswordPlaceholder')}
+                  autoComplete="new-password"
                 />
               </MAdminField>
               <MAdminField label={t('settings.role')}>
diff --git a/client/src/pages/admin/AdminUserModals.tsx b/client/src/pages/admin/AdminUserModals.tsx
index e37e7aaa4..81d84b5a2 100644
--- a/client/src/pages/admin/AdminUserModals.tsx
+++ b/client/src/pages/admin/AdminUserModals.tsx
@@ -31,6 +31,7 @@ import { SETTINGS_BUTTON, SETTINGS_BUTTON_DANGER } from '../../components/Settin
 import type { TranslationFn } from '../../types';
 import type { useAdmin } from './useAdmin';
 import PasswordChecklist from '../../components/shared/PasswordChecklist';
+import { NO_AUTOFILL } from '../../utils/noAutofill';
 
 interface AdminUserModalsProps {
   admin: ReturnType<typeof useAdmin>;
@@ -66,6 +67,8 @@ function PasswordInput({
       <input
         id={id}
         type={shown ? 'text' : 'password'}
+        // Another user's password: never the admin's own, and a manager may offer a fresh one.
+        autoComplete="new-password"
         value={value}
         onChange={(e) => onChange(e.target.value)}
         placeholder={placeholder}
@@ -166,6 +169,7 @@ export default function AdminUserModals({ admin, t }: AdminUserModalsProps): Rea
               onChange={(e) => setCreateForm((f) => ({ ...f, username: e.target.value }))}
               placeholder={t('settings.username')}
               className={INPUT}
+              {...NO_AUTOFILL}
             />
           </EditorField>
           <EditorField label={`${t('common.email')} *`} htmlFor={`${createId}-email`}>
@@ -176,6 +180,7 @@ export default function AdminUserModals({ admin, t }: AdminUserModalsProps): Rea
               onChange={(e) => setCreateForm((f) => ({ ...f, email: e.target.value }))}
               placeholder={t('common.email')}
               className={INPUT}
+              {...NO_AUTOFILL}
             />
           </EditorField>
         </div>
@@ -239,6 +244,7 @@ export default function AdminUserModals({ admin, t }: AdminUserModalsProps): Rea
                   value={editForm.username}
                   onChange={(e) => setEditForm((f) => ({ ...f, username: e.target.value }))}
                   className={INPUT}
+                  {...NO_AUTOFILL}
                 />
               </EditorField>
               <EditorField label={t('common.email')} htmlFor={`${editId}-email`}>
@@ -248,6 +254,7 @@ export default function AdminUserModals({ admin, t }: AdminUserModalsProps): Rea
                   value={editForm.email}
                   onChange={(e) => setEditForm((f) => ({ ...f, email: e.target.value }))}
                   className={INPUT}
+                  {...NO_AUTOFILL}
                 />
               </EditorField>
             </div>
diff --git a/client/src/utils/noAutofill.ts b/client/src/utils/noAutofill.ts
new file mode 100644
index 000000000..b7bcf1999
--- /dev/null
+++ b/client/src/utils/noAutofill.ts
@@ -0,0 +1,15 @@
+/**
+ * For a field that holds somebody else's details: a place's e-mail and phone,
+ * the account an admin is creating. Password managers read such a field as a
+ * login and offer, or simply fill in, the signed-in user's own credentials.
+ * `autocomplete="off"` alone does not stop them (1Password ignores it on
+ * purpose), so each one gets its own opt-out. Never use it on a login or on the
+ * user's own account fields, where autofill is wanted.
+ */
+export const NO_AUTOFILL = {
+  autoComplete: 'off',
+  'data-1p-ignore': 'true',
+  'data-lpignore': 'true',
+  'data-bwignore': 'true',
+  'data-form-type': 'other',
+} as const;