Waterproof watches are made differently from other watches due to seals placed around the case back to prevent water from entering the watch. This tight seal can make it difficult to open the case back to repair the watch or change the battery. A tool is necessary to properly open the case back without damaging the watch. Waterproof watch case opener tools are available online, at watch repair stores or some specialised jewellers. Use caution when using the tool and ask an authorised watch repair shop for assistance if you experience difficulties or have any questions.
Turn the watch over to expose the case back. Set the tool in the slots on the back of the watch and hold it upright so that the turning ring is in the middle.
Remove the watch band if it is hindering the process of removing the case back.
Tighten the turning nut on the side of the tool until snug.
Hold the watch in your hand or set it on a padded surface and attempt to turn the tool counterclockwise.
Continue turning the tool counterclockwise until the case back pops slightly and loosens. Unscrew the turning nut on the tool and set it aside. Lift off the case back.
Stop if you feel resistance or if the case back will not open. Consult an authorised watch repair store for assistance to prevent from damaging the watch.