The GD100 is the big-digit digital G-Shock with the bright LED backlight, and it is one of the simplest to set because there are no hands to worry about. This guide walks through the time, DST, alarms, world time and the backlight on module 3263.
Buttons
On every G-Shock the four buttons are named the same way: A is top-left (Adjust), B top-right, C bottom-left (Mode), D bottom-right. Your watch's module number is engraved on the case back; Casio's manual for that module is the final word.
Set the time
- In timekeeping, hold A about two seconds until the city code flashes.
- Pick your city with D / B.
- Press C to step: DST → 12/24-hour → seconds → hour → minutes → year → month → day. Change each with D / B; D resets seconds to 00.
- Press A to save.
Alarms
Press C to the alarm screen. Press D to cycle the alarms (AL1 to AL4 and the snooze alarm SNZ). Hold A until the hour flashes, set with D / B, move with C, press A. On the alarm screen, D toggles the selected alarm; SIG is the hourly chime.
World time
Press C to WT. D scrolls cities; hold A then press D to switch that city's DST. Press B to swap your home city and the displayed world-time city, which is the fastest way to handle travel.
Backlight
Press B. Hold B in timekeeping to turn the auto-light on or off. The GD100's high-brightness LED and light-guide plate are the reason it reads better in the dark than most G-Shocks.
Battery
The GD100 is not solar; a CR2025 lasts about seven years. When the display dims or the backlight weakens, it is the battery, and it is a five-minute swap for a jeweler.
Frequently asked questions
How do I set the time on a G-Shock GD100?
Hold A until the city flashes, pick the city, then C through DST, 12/24, seconds, hour, minutes and date; press A to save.
How many alarms does the GD100 have?
Four daily alarms plus a snooze alarm.
How do I swap home and world time?
Press B on the world-time screen.
Is the GD100 solar?
No. It uses a CR2025 battery, about seven years.
What module is the GD100?
3263.
The bottom line
The GD100-1B is the easiest G-Shock to set: hold A, city, then straight through the fields.
Related reading
How to set the time on any G-Shock
Best G-Shock for EDC
How to set a G-Shock GA100
