Instructions on how to change your watch strap can be found in the "Owner's Guide" that you received with your watch and under "Support" in the footer menu. The tool which is used is included at the bottom of your watch case. You can also use a similar, small item to adjust the size.Please Be Advised: Due to the sandblasted coating on the mesh strap, the attached clasp may initially be a bitstiff and, therefore, appear difficult to open and close.However, by following the instructions advised, you can wiggle the clasp by stating and stopping applying pressure to it until it becomes looser and easy to adjust.