How do I change the battery?

[PandaNix]

Both my AirTags keep sending alert that the battery needs replacing. Do I have to go to an apple shop or can I change myself?

 

[Jonnod III]

How to replace the battery in your AirTag - Apple Support

You can replace the battery in your AirTag. Here's how.

support.apple.com

 

[arw]

And pay attention to the warning of CR2032 batteries with bitterant coating (introduced for child safety to avoid accidental swallowing).
[Image of the circular coating on the top]
Apparently Apple does not follow the recommendation for contact positioning in their Airtags so the minus pole overlaps with the (insulating) coating. [link]
There are several reports of successfully rubbing off the coating with isopropyl alcohol - or even water.