Use Dual SIM with Apple Watch GPS + Cellular models
If you set up multiple cellular plans using Dual SIM on your compatible iPhone, you can add both plans to your Apple Watch. Then you can choose which one your watch uses when it connects to cellular networks.
Set up multiple cellular plans
If you set up Dual SIM on your iPhone XS, iPhone XS Max, or iPhone XR or later, you can add both cellular plans on your Apple Watch Series 4 or later, as long as each plan is eligible and from a supported carrier.
You can set up one plan when you set up your watch for the first time. Then you can set up your second plan later in the Apple Watch app:
On your iPhone, open the Apple Watch app.
Tap the My Watch tab, then tap Cellular.
Tap Set Up Cellular or Add a New Plan. If you didn't add your first plan during setup, you can add it here.
Follow the onscreen steps to choose the plans that you want to add to your Apple Watch. Each cellular plan will be billed separately. If you need help, contact your carrier.
You can add up to five cellular plans to your Apple Watch. However, your Apple Watch can only connect to one at a time. If you have an enterprise or corporate cellular service plan, check with your company or carrier to see if they support this feature. Pre-paid accounts and some older accounts aren’t currently supported. To make sure that your account is eligible, contact your carrier.
Switch between plans
On your iPhone, open the Apple Watch app.
Tap the My Watch tab, then tap Cellular.
Your plan should automatically switch. If it doesn't switch, tap the plan that you want to use. It might take about a minute for your Apple Watch to switch plans.
You can also switch plans directly from your Apple Watch. Go to Settings > Cellular or Settings > Mobile Data, then choose the plan that you want your watch to use when it connects to cellular.
Here's how your Apple Watch receives calls and messages
When your Apple Watch is connected to your iPhone, you can get calls and messages from both plans. Your watch shows which cellular plan you received a notification from by showing a badge with the first letter of the line. If you respond to a call or message, your watch automatically responds from the line that you received the call or message on.
When your Apple Watch is away from your iPhone and connected to cellular, you can get calls and messages from your active plan. If your iPhone is turned on, even if it isn't nearby, you can get messages and notifications about calls from your other plan. If you respond to a call, your watch automatically calls back from your active plan. If you respond to an SMS message, your watch automatically texts back from the plan that you received the message on. You can respond to iMessages as long as there's an active data connection from any plan. If you want to change your active plan, you can manually switch between plans from Settings on your Apple Watch.
