The Time Timer Watch takes the battery type CR2032.
With the updated Time Timer Watch models follow these steps to replace battery.
Once you have purchased the battery, replace by:
1. Use a coin or flat head screw driver to open the battery cover by turning counter clock wise.
2. Gently lift the tab and remove current battery.
3. (With tab still lifted) Insert the new battery under the tab.
4. Replace the back and close battery cover by turning clockwise.
If you have the Time Timer Watch PLUS adult (charcoal) or child (charcoal, lime green, sky blue, berry pink):
The Time Timer Watch PLUS will require a professional to replace the battery. Most jewelry shops offer battery replacements for watches. Just ensure they know the battery type CR2032 is required for the Time Timer Watch PLUS.