Depth app stopped working suddenly on my Apple Watch Series 10

Any error messages shown?

Does the Water Lock switch on automatically as soon as the watch is submerged?

Did you try to force restart your watch by pressing and holding the Digital Crown and the Side button together for about 10sec, until the Apple logo comes back again?

If this does not work, reinstalling the app would be the next step.

You can contact the official Apple Support about this, they can diagnose your watch online. My Ultra has an extra opening for the depth sensor, which recognizes when the watch is being submerged. This also works if I fill up a bucket with water and put in my watch arm.

I could not find any information, where this sensor is located on the Series 10.

Did you already try to erase the watch and set it up as a new device, without using the latest backup? If the sensor worked in the past, this could rule out a software issue.

You're welcome🙂

Good Luck!

Does the watch still measure the elevation, for example using the Compass app?

Did you check if all openings are free of debris or lint?

How to clean your Apple Watch – Apple Support (AU)

Same, lost mine the 29th updated the 30th, still does not read anything or auto launch when submerged