Your Apple Watch Series 10 is supposed to mirror your iPhone without you thinking about it, so it is jarring when notifications stop landing, your activity rings stall, or the watch face shows a disconnected status. Because there is no master sync switch on the Apple Watch, the watch updates itself automatically whenever it is connected and in range of your iPhone, which means a stalled sync almost always points back to a broken connection rather than a setting you forgot to flip. The good news is that the link between the two devices runs over a short set of radios, and walking through them in order usually gets everything talking again. The fixes below move from the quickest, safest checks to the more involved steps, with the official reset and support paths saved for last.
Before you start, it helps to know how the connection works. When your iPhone is nearby, the watch syncs over Bluetooth. If Bluetooth is not available and compatible Wi-Fi is, your Apple Watch uses Wi-Fi instead. On GPS plus Cellular Series 10 models, cellular can act as a further fallback. Knowing this is why the first fixes focus on getting those radios back in play.
Bring the Watch and iPhone Back Within Range of Each Other
The simplest reason your Series 10 stops syncing is distance. Apple's guidance is to keep your Apple Watch and paired iPhone close together so that they are in range of one another, since the Bluetooth handoff that carries most syncing only works over a short reach.
If you left your phone in another room or in a bag across the office, that gap alone can pause activity updates and notifications. Move the two devices next to each other and give them a moment to reconnect before assuming anything is actually broken. This is the very first sync fix worth trying.
Clear Airplane Mode and Confirm Wi-Fi and Bluetooth Are On
Airplane Mode silences the exact radios your watch relies on, and it is easy to enable by accident on either device. Start with your iPhone, then check the watch.
On your iPhone, make sure that Airplane Mode is off and that Wi-Fi and Bluetooth are on. To check, press the side button to open Control Center. If any of those radios are switched off, the connection that your watch syncs over has nowhere to travel.
Then look at your watch. If you see the Airplane Mode icon on your watch face, open Control Center on the watch, then turn off Airplane Mode. A stray Airplane Mode toggle, or a disabled Wi-Fi or Bluetooth radio, is one of the most common reasons syncing stops, so confirm both devices are fully connected before moving on.
Restart Both Devices to Reset the Connection
If the radios are all on and the devices are close together but syncing is still stuck, a restart clears temporary glitches on either side. Apple recommends restarting your Apple Watch and restarting your iPhone when the connection fails.
To restart the watch normally, follow this sequence exactly.
- 1.Press and hold the side button until the sliders appear.
- 2.Tap the Power Button.
- 3.Drag the Power Off slider to the right to turn the watch off.
- 4.To turn it back on, hold down the side button until the Apple logo appears.
Restart your iPhone as well, then bring the two devices together and let them reestablish the link. A clean restart on both ends resolves a surprising share of sync hiccups.
Force Restart the Watch When It Is Frozen or Unresponsive
Sometimes the watch is too stuck to complete a normal restart, with the screen unresponsive or hung. In that case, a force restart is the next step. Apple says to do this only when you cannot complete a normal restart.
To force restart the Apple Watch Series 10, hold down the side button and the Digital Crown at the same time for at least 10 seconds, until the Apple logo appears. Do not let go early, because you are waiting specifically for that logo to show up, which confirms the restart took. Once it boots back up, check whether the connection and syncing have recovered.
Update watchOS to the Latest Version
Outdated software on the watch can break the connection between it and your iPhone, so installing the latest watchOS is worth doing if the steps above did not help. You can run the update from your phone or directly on the watch.
To update from the iPhone, open the Apple Watch app, tap the My Watch tab, tap General, then tap Software Update. Keep the watch on its charger and at least 50 percent charged while it installs.
Alternatively, on a watch running watchOS 6 or later that is connected to Wi-Fi, you can update on the device itself. Open the Settings app, tap General, then tap Software Update, then tap Install if an update is available. The watch restarts on its own when the update finishes, and you can check whether syncing returns afterward.
Unpair the Watch and Pair It Again
If your Series 10 still cannot connect after restarting and updating, Apple advises unpairing it from your iPhone and then pairing the two again. This is a more involved step. Before you start, understand that unpairing restores the watch to factory settings and removes Activation Lock. Your data is protected because your iPhone creates a new backup of your Apple Watch before erasing it, which you can use to restore the watch after re-pairing.
Here is how to unpair from your iPhone.
- 1.Open the Apple Watch app.
- 2.Tap My Watch, then tap All Watches.
- 3.Tap the Info button next to your watch.
- 4.Tap Unpair Apple Watch.
After the watch is unpaired and erased, pair your Apple Watch and iPhone again, and choose to restore from the backup your iPhone created. This rebuilds the connection from scratch, which often clears stubborn sync problems that the lighter fixes could not.
When Syncing Still Will Not Work
If reconnecting, restarting, updating, and re-pairing all fail to fix syncing, the problem may be something beyond a software hiccup, such as a hardware or account issue. At that point, Apple's troubleshooting flow ends with getting help.
Reach out to Apple Support at support.apple.com so they can check what is going on with your specific watch and account. Having already worked through the steps above will help, since you can tell them exactly what you tried and what happened.
Frequently Asked Questions
Is there a sync on or off switch on the Apple Watch Series 10
No. There is no single sync toggle in Apple's documentation. Your Apple Watch syncs automatically when it is connected to your iPhone and the two are in range, so fixing a sync problem means restoring that connection rather than flipping a switch.
What does my Apple Watch use to sync if my iPhone is not nearby
The watch uses Bluetooth when your iPhone is near. If Bluetooth is not available and compatible Wi-Fi is, your Apple Watch uses Wi-Fi instead. On GPS plus Cellular Series 10 models, cellular can act as an additional fallback connection.
Will unpairing my Apple Watch delete my data
Unpairing restores the watch to factory settings, but your iPhone creates a new backup of your Apple Watch before erasing it. You can use that backup to restore the watch after you pair the two devices again, so your data and settings are preserved.
How do I force restart an Apple Watch Series 10 that is frozen
Hold down the side button and the Digital Crown at the same time for at least 10 seconds, until the Apple logo appears. Apple recommends doing this only when you cannot complete a normal restart.
What do I need to run watchOS 26 on my Series 10
Per Apple, watchOS 26 requires an iPhone 11 or later, or an iPhone SE 3rd generation or later, running iOS 26. The watchOS 26 user guide lists Apple Watch Series 10 as a compatible model.
