Check your phone’s “Trash” or “Recently Deleted” folder (if available)
Restore from an Android backup (Google One/Google Drive) if you have one from before deletion
Use the carrier’s message backup service (if your carrier offers it)
If you use a messaging app with cloud sync (e.g., Google Messages with backup), restore the app backup
For iPhone, restore from an iCloud or iTunes backup made before the messages were deleted
Use iCloud Messages sync to re-download messages if they were still in iCloud
If you have device storage access tools, stop using the phone immediately and contact a data recovery service
Contact your carrier or employer-managed IT (if applicable) for any managed retention options
If the messages were sent to another number, ask the recipient to check their copy
Check whether the messages are available in message-export files or prior backups (including third-party backup exports)