apple watch says no sim

Hello sarahsummer2016s.

Thank you for using Apple Support Communities. Let's try some basic troubleshooting steps to see if we can get this issue sorted out. First, try to restart both your iPhone and Apple Watch:

Restart your Apple Watch - Apple Support

1.) Press and hold the side button until you see the Power Off slider.

2.) Drag the Power Off slider.

3.) After your watch turns off, press and hold the side button again until you see the Apple logo.

Restart your iPhone - Apple Support

If you're using an iPhone X, 11, 12, or 13:

1.) Press and hold either volume button and the side button until the power-off slider appears.

2.)Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.

3.) To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.

If that doesn't help, you'll want to make sure that your Apple Watch and companion iPhone are fully updated on their software versions. This can sometimes help resolve various issues. Just in case, the resources below can guide you through the update process: Update your iPhone, iPad, or iPod touch - Apple Support

1.) Back up your device using iCloud or your computer.

2.) Plug your device into power and connect to the internet with Wi-Fi.

3.) Go to Settings > General, then tap Software Update.

4.) If you see two software update options available, choose the one that you want to install.

5.) Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.

Update your Apple Watch - Apple Support

1.) Make sure that your Apple Watch is at least 50 percent charged.

2.) Connect your iPhone to Wi-Fi.

3.) Keep your iPhone next to your Apple Watch, so that they're in range. 

4.) On your iPhone, open the Apple Watch app, then tap the My Watch tab. 

5.) Tap General > Software Update.

6.) Download the update. If asked for your iPhone passcode or Apple Watch passcode, enter it. 

7.) Wait for the progress wheel to appear on your Apple Watch. It could take from several minutes to an hour for the update to complete. 

Feel free to keep us posted on your results. We hope these steps are helpful. Cheers.