Recently I've got some notifications from my iPhone that some of my AirTags batteries were almost depleted.

What you need is just a new CR2032 battery and your thumbs.

Press the metallic side with two of your thumbs and rotate it counterclockwise.

Take out the old battery and install the new one.

Put back the metallic cover, use two of your thumbs to rotate it clockwise, and finally lock the battery.

If it's successful, you're going to hear a sound coming from the AirTag.

That's all! Thanks for reading.