BagGuard

Leave your phone in your bag and go swimming. BagGuard watches the bag with the phone's motion sensor, and if it is picked up your watch buzzes — so you find out while you can still do something about it, instead of when you come back.

• Arm from the phone or straight from your wrist
• Adjustable sensitivity, and an optional "sustained movement" requirement so a knock against the bag does not set it off
• A test mode that shows exactly what the sensor sees before you trust it
• Alerts reach your watch over the companion link, over your local Wi-Fi, or over the internet — whichever is available
• A phone siren as a last resort if nothing can reach your watch
• No account, no ads and no analytics. Optional internet alerts use ntfy.sh; see the privacy policy for details

Guarding is free for the first five hours in total. Only time while the guard is actually armed counts — looking at the app or changing settings costs nothing. When the free time runs out, a single one-off purchase inside the app unlocks unlimited guarding for good. There is no subscription and nothing expires.

On your watch, BagGuard shows the guard on your watch face while it runs, adds a tile you can swipe to for arming and disarming, and offers a complication you can place on your own watch face to arm with one tap.

BagGuard is not a security guarantee. It tells you that your bag moved; what happens next is up to you.

Requires BagGuard on an Android phone and a paired Wear OS watch.