Phase 1 — The hardware swap
Power off: before opening the watch, hold down the power button and turn the watch completely off.
Replace the SIM: follow the instructions for your watch — Insert your SIM into your Adventurer or Insert your SIM into your Loop.
Power on: turn the watch back on and wait for the signal bars to appear, indicating it has connected to the network.
Note: if you ported your number to Spacetalk, there's nothing further to do. If your new SIM comes with a new number, follow Phase 2 below.
Phase 2 — Update the app
Once the watch is back online, update the phone number in the app so features like calling and messaging keep working.
Open the Spacetalk app on your phone.
Tap the Profile icon (bottom-right of the menu).
Select the member whose watch you've just updated.
Tap the member's Watch to open Watch Settings.
Scroll down to Phone Number.
Enter the new phone number and tap Update. You'll see a “Phone number updated” confirmation when complete.
Important — update your phone contacts
Updating the number in the Spacetalk app makes the watch work correctly within the app. You must also manually update the watch's number in your personal phone contacts.
Why? if you've saved the watch's number in your phone's address book (so you can call it from your dialer), that contact won't update automatically.
Action: make sure every family member who has the watch's number saved updates it to the new number, so they can still call the watch directly.