If your contacts are stored in iCloud, Apple provides a way to restore an earlier archived version of your contacts. This is useful when contacts were accidentally deleted or changed across synced devices.
- On a web browser, sign in to iCloud with the Apple Account used for your contacts.
- Open the account’s data-recovery options and choose Restore Contacts.
- Select an archive from before the contacts disappeared.
- Confirm the restore and allow time for the restored contacts to sync back to your iPhone.
Restoring an archive replaces the current iCloud contact set, although Apple normally archives the current version first so it can be restored again if needed.
If your contacts come from Google, Microsoft Exchange, or another account, check that account instead. On the iPhone, you can also review Settings > Apps > Contacts > Contacts Accounts to make sure the account containing the missing contacts is still enabled.