Important note: Wear Installer is intended for installing watch apps which have been included by their developer(s) in the corresponding phone apps. Or apk files built for WearOS (via the Custom APK option). Wear Installer does not install phone apks directly to WearOS devices. To install a phone apk to your watch, use Wear Installer 2.
Update 17 October 2022: from version 1.08 onwards, Wear Installer runs only on your Android phone. There is nothing to run on your watch. However the app still has the same functionality as before, and runs more reliably.
Most WearOS apps can be installed from the Google Play Store and this is the preferred method of installation. However some legacy and/or open source WearOS apps aren’t available in the Play Store. In these cases, Wear Installer can help by transferring the watch component from your Android phone and installing it using something called the Android Debug Bridge, or ADB for short.
You can install Wear Installer on your Android phone by following this link. To see examples of how to use Wear Installer on a WearOS 2 device (Skagen Falster 3) please see this YouTube video and on a WearOS 3 device (Galaxy Watch 4) please see this YouTube video. However note that the watch component of Wear Installer is no longer required, so ignore that part of the video.
If you are having problems getting Wear Installer working, please see below:
General best practice: if you are having problems, restart both your phone and your watch. Check that Wifi and Bluetooth are enabled on both your phone and your watch. Check that the WearOS app on your phone (or the Galaxy Wearable app if using a Galaxy Watch 4) is showing that your watch is connected to your phone. On your watch, check that you have enabled ‘ADB debugging’ and ‘Debug over wifi’ in the developer settings, as shown in the videos. Check that you have the correct IP address for your watch (often something like 192.168.1.x). Enter this ip address into the Wear Installer phone app.
Wear Installer phone app says ‘Watch APK not found’ or similar: this message means that the phone app you are trying to install to your watch has not been built by the developer to include a watch component. Wear Installer won’t be able to help you in this case.
Wear Installer extracts the watch APK and says ‘Sending to watch’ but nothing happens: Please allow up to 10 minutes for the transfer to take place – you’ll see a message when it’s done. For best results, connect both your phone and watch to a power supply and keep the displays awake on both devices. Make sure Bluetooth is enabled on both devices.
The watch APK successfully transferred but there is a ‘connection failed’ message: this message means that the phone and watch have been unable to connect over wifi. Re-check that you have correctly entered the watch’s ip address in the Wear Installer phone app. Check that your phone has wifi turned on (the watch’s wifi will have been turned on when you set ADB debugging). Check that both phone and watch are reasonably close to your wifi router – note that the watch has a small aerial so it cannot connect to wifi over longer distances.
‘Connection failed’ message persists despite above checks: it can happen that your phone connects to a 5Ghz wifi network while your watch connects to a 2.4Ghz network. With most wifi routers this is not a problem, and Wear Installer can still make a wifi connection between phone and watch. However some people have reported that temporarily turning off the 5Ghz band on their router forces phone and watch to connect to the 2.4Ghz network – and this resolves the ‘connection failed’ message that Wear Installer reports.
If all else fails: an alternative method is here.