New phones tend to arrive in December, and the old one gets wiped within the hour. The usual losses are not photos, which both companies’ tools handle well, but things nobody thinks about: authenticator codes, WhatsApp history, the SIM or eSIM, and text messages that keep landing in an iMessage account the phone no longer uses. This checklist follows the order in which those problems bite.

Before you touch the new phone

  1. Back up the old phone first, and look at the date. A transfer tool copies; it does not replace a backup.
  2. List your two-factor apps. Open each account’s security page and note which ones use an authenticator app, a text message or a passkey. The next section covers moving them; do not skip it.
  3. Update the apps on the old phone. Apple’s Android-to-iPhone page tells you to update Chrome on the Android phone if you want bookmarks to transfer.
  4. Check storage on the new phone. Both Apple and Google warn that content which does not fit will not fully transfer.
  5. Charge both phones and keep them plugged in. Google says transfers usually take under 30 minutes but can take a few hours with a lot of data.

Two-factor codes, the real loss risk

Google’s help page for Authenticator describes two ways to move codes. The simple one: install Authenticator on the new phone, tap Get Started and sign in to the same Google account, and codes that were synced to the account appear automatically (Google lists Authenticator 6.0 or later on Android and 4.0 or later on iOS). The manual one, for codes not saved to an account: on the old phone, open the menu, choose Transfer codes, then Export codes; on the new phone choose Transfer codes, then Import codes and scan the QR codes.

Google’s warnings are worth repeating: deleting a code removes it from every device where your codes sync, and codes that were never synced to an account exist only on the old phone. So do not wipe the old phone until every important site has been tested with the new one. For other authenticator apps, use their own transfer feature; we did not verify those. As a backstop, check whether each important account offers recovery codes, and print or store them somewhere that is not on the phone.

Passkeys are another trap. Google’s upgraded transfer, available on some Android 17 phones, lists passwords and passkeys among the data types it copies; the classic methods do not. If your new phone does not support the upgraded process, assume your passkeys stay behind. Plan to sign in to important accounts with a second method and register new passkeys on the new phone. Our guide to how passkeys sync across devices explains how that works.

iPhone to Android

Data Wireless (Android Switch app) Cable
Contacts, calendars, photos and videos Yes Yes
Messages, notes No Yes
WhatsApp history No Yes
Apps Free Google Play apps only No
Passwords and passkeys, Wi-Fi networks, call history No No (upgraded process only)

That table is Google’s, simplified. The cable route moves the most in the classic process. Steps from Google’s page: turn off iMessage on the iPhone before you start, connect the iPhone to Wi-Fi, and use the iPhone’s charging cable (plus a USB-A to USB-C adapter if needed). Tap Trust when prompted, choose the data types and tap Copy. For wireless, you need iOS 15 or later, install Android Switch from the App Store on the iPhone and scan the QR code on the Android screen.

What does not transfer, per Google: photos and videos stored in iCloud, paid apps and in-app purchases, Safari bookmarks and health data. After setup, switch from iMessage to Google Messages, and use Google Photos’ transfer process for iCloud photos.

Android to iPhone

Apple’s steps: during iPhone setup choose Set Up Without Another Device on the Quick Start screen, then on the Transfer Your Apps & Data screen tap From Android and Transfer with App. On the Android phone, open Move to iOS, enter the six- or ten-digit code that the iPhone shows, join the iPhone’s temporary Wi-Fi network and choose what to move. Keep both phones near each other and plugged in until the loading bar on the iPhone finishes, even if Android says it is done. Apple says using other apps or taking a call on the Android phone during the transfer can stop content from moving.

Apple’s list of what moves includes contacts, message history, WhatsApp messages and media, photos, videos and albums, files and folders, mail accounts, calendars, voice memos, call history, accessibility settings, web bookmarks and some free apps found on both stores. Music, books and PDFs must be moved by hand. If the iPhone is already set up, Apple says you must erase it before using the app. On some Android 17 phones, Apple also describes a route that skips the app (“Transfer without App”), including eSIM transfer, but it depends on the manufacturer’s support.

WhatsApp, the SIM and iMessage

  • WhatsApp: its help center says you can transfer chats only if WhatsApp is not yet activated on the new phone, to uninstall it on the new phone first, and that chats cannot be moved to a new phone number. If a transfer fails, the chats remain on the old phone, so do not delete anything until you have confirmed the result.
  • SIM or eSIM: Apple says you may be asked to activate an eSIM during setup, and your carrier may send you to its website to finish. Allow time for this. Decide before the swap whether you are moving the physical SIM or an eSIM.
  • iMessage: if you leave Apple, deregister it. Apple’s steps: put your SIM back in the iPhone, make sure cellular data is on, and turn off iMessage under Settings, Apps, Messages, then turn off FaceTime under Settings, Apps, FaceTime. If you no longer have the iPhone, use Apple’s online form at selfsolve.apple.com/deregister-imessage/. Texts should arrive right away, though Apple says it can take a few hours for some Apple devices to notice.

The week after: a short audit

  1. Send and receive a normal text and a group chat with an iPhone user.
  2. Sign in to the five accounts that matter most (email, bank, password manager, cloud storage, work) and complete the two-factor step on the new phone.
  3. Open the photo app and compare the photo count to the old phone.
  4. Check that wallet cards, transit passes and smartwatch pairing are set up again. We did not verify these paths in either company’s help pages, so check each app’s own instructions.
  5. Only then erase the old phone, using our guide on resetting a phone before you sell or gift it. If the new phone is a Galaxy, see our note on the One UI 9 rollout before you plan an early reset.

One more practical point: if the old phone has photos backed up to Google or iCloud, the backup storage meter may fill up during the move. Our explainer on Android backup storage shows how to see what is taking the space.

Sources

Checked against Apple, Google and WhatsApp help pages on October 30, 2026. Data types and device support change by model and country.

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