It is about a year.
So unlike GPS trackers with limited battery life, you can just attach the KiteboardTag and forget about it.
Once the battery gets low, you’ll get an message on your Apple device.
Simply unscrew the silver part of the AirTag and replace the coin type battery.
Ikea sells 8 of them for €1,99.
8 years worth of battery life for two euro’s, not a bad deal.