Limit or Turn Off Cellular
If you have a cellular-capable Apple Watch, then you should know that relying on LTE data will drain your battery faster than almost anything else you do on your device.
For most folks, this isn’t a common problem; even when cellular data is on, the Apple Watch only uses it when it has no other option. If your iPhone is nearby and turned on, your Apple Watch will connect through that instead, relying on the iPhone’s much larger battery to handle the heavy lifting of your data onto the cellular network.
Further, even if your iPhone isn’t nearby, your Apple Watch still automatically connects to any Wi-Fi network that your iPhone knows about. That will use a lot less battery life than switching over to cellular.
You can check what kind of connection you’re using just by swiping up from your watch face to bring up the Control Center. If you’re connecting through your iPhone, you’ll see a small green iPhone icon at the very top. Otherwise, you’ll see a Wi-Fi symbol or a series of cellular bars, depending on which type of network connection you’re using.
There’s also a button for Cellular Data in the watchOS Control Center, just like on the iPhone. This will be green when cellular data is actively in use, white when cellular data is on standby (meaning it’s enabled, but you’re on Wi-Fi or connected through your iPhone instead), or grey if you’ve manually turned cellular data off — which you can quickly do by tapping on this button.
The most common way that most Apple Watch users get tripped up with cellular power consumption is when going on workouts without their iPhone in tow. You may not care about receiving phone calls or messages while you’re working out, but that doesn’t mean your watch isn’t still consuming power just by maintaining a connection to the cellular network.
If you’re finding your watch drains more quickly after these types of workouts, either disable cellular data or bring your iPhone along on your run to provide the power to keep you connected.