For 27 years, Casio has been manufacturing G-Shock watches that are designed to be the toughest watches on the market. From 1983 to 1997, Casio made the G-Shock watches based on its "Triple 10" development concept. Those watches had a 10-meter free-fall endurance, 10-bar water resistance and a 10-year battery life. Since 1997, Casio has been using built-in solar panels to power its watches. It isn't surprising that the battery-powered G-Shocks are still around because they were built to last but every decade the battery might need to be changed.
Turn the watch over and locate the screws holding the backplate to the watch.
Remove the screws and remove the backplate using a micro Phillips-head screwdriver. Some models combined various size screws so be careful to remember where each screw was removed from.
Using the tweezers, carefully remove the black rubber protector covering the battery.
Use the needlepoint tweezers (a pin or needle will work too) to unlock the clasp holding the battery in place. The clasp can be found at the bottom right-hand corner of the battery.
Use the tweezers to carefully remove the old battery.
Locate the new battery and use the tweezers to place the new battery into the watch. The letters on watch batteries should always be face up.
Use the tweezers to slide the clasp back in to place. This secures the new battery.
Locate the letters "AC" near the battery. Using the tweezers, press the AC contact into the exposed part of the battery beside it. This resets the internal memory of the watch.
Remove the rubber seal/gasket that runs the perimeter of the watch back. Apply a small amount of the silicone lubricant to the seal. This helps the seal stay water-resistant and flexible.
Replace the rubber seal and black rubber shock protector.
Replace the back cover and secure the screws in place.
If you have a G-Shock dive watch, you will want to have the battery professional changed. Dive watches are pressure sealed to ensure they remain water tight.