The checklist, in order
- Back up. iPhone: Settings → [your name] → iCloud → iCloud Backup. Android: Google backup in Settings, or a copy on your computer.
- Unpair your Apple Watch. Watch app → My Watch → All Watches → (i) → Unpair Apple Watch: its Activation Lock is turned off too.
- Move your two-factor codes. Transfer your authenticator apps and check that the new phone receives codes.
- Transfer your eSIM to the new phone, or ask your carrier.
- Switching to Android? Deregister your number from iMessage (Apple’s “Deregister iMessage” page), or texts can go missing.
- Sign out. iPhone: Settings → [your name] → Sign Out (Find My turns off). Android: remove your Google account, and your Samsung account on a Galaxy, under Accounts in Settings.
- Erase. iPhone: Settings → General → Transfer or Reset iPhone → Erase All Content and Settings. Android: factory data reset in Settings.
- Take out the SIM card, and the memory card if your phone has one.
- Check it has left your accounts. On iCloud.com or in your Google account, remove it from your list of devices.
- For the sale: a photo ID. The charger or box are welcome, but not required.
What SubSell does next
Even after your reset, every phone we buy goes through professional data-erasure software before any resale: photos, messages, accounts and files are wiped for good. No one at the shop looks at your data. The whole process: how we erase your data.