Model guide · Reviewed
G-SHOCK G-7900: Size, Battery Life, Water Resistance & Specs
Short answer
The G-SHOCK G-7900 is a rugged digital G-SHOCK with a tide and moon graph, measuring 52.4 × 50 × 17.7 mm.
- Thickness
- 17.7 mm
- Weight
- 68.2 g (2.4 oz)
- Water resistance
- 200 m / 20 bar
- Power
- 2-year battery
The G-7900 (2009) is an outdoorsy digital G-SHOCK with a tide and moon graph for ocean and outdoor use. It runs about two years on a CR2025 battery and weighs 68.2 g. Our red build is based on the G-7900A-4 variant.
G-7900 specifications
Casio's specifications for the stock G-7900-1. Custom builds can differ; see the notes below.
| Reference | G-7900-1 |
|---|---|
| Module | 3194 |
| Display | Digital |
| Shape | Rugged rounded |
| Case size (L × W × H) | 52.4 × 50 × 17.7 mm (2.06 × 1.97 × 0.7 in) |
| Weight | 68.2 g (2.4 oz) |
| Case | Resin |
| Band | Resin |
| Water resistance | 200 m (660 ft, 20 bar) |
| Power | Battery: CR2025, about 2 years |
| Tough Solar | No |
| Multi-Band 6 (atomic time) | No |
| Bluetooth | No |
| Light | Backlight |
| Launched | 2009 |
| Casio U.S. list price | $120 |
Features
- Tide and moon graph
- World time
- Stopwatch
- Countdown timer
- 5 multi-function alarms
What is the G-SHOCK G-7900?
The G-SHOCK G-7900 is a rugged digital Casio watch from 2009 with a tide and moon graph. It uses module 3194 and runs on a CR2025 battery.
How long does the G-7900 battery last?
The G-7900 runs about 2 years on a CR2025 battery, according to G-Central's specification sheet. It is not solar powered.
How big is the G-7900?
The G-7900 measures 52.4 × 50 × 17.7 mm and weighs 68.2 g, according to G-Central. That is about 2.1 × 2 × 0.7 inches, similar in size to the GW-6900.
What does the G-7900 tide graph show?
The G-7900's tide and moon graph shows the approximate tide level and moon phase for a set location. It is a planning aid, not a navigation instrument, so check local tide tables for anything safety related.
Is the G-7900 water resistant?
The stock G-7900 is rated 200 m (660 ft, 20 bar) water resistant, like other G-SHOCKs. Custom builds should be confirmed with us before swimming.
How much does a G-7900 cost?
Casio's U.S. list price for the G-7900-1 is $120, as recorded by G-Central. Bezelwright currently lists 1 custom G-7900 builds from $150.
Is the G-7900 right for you?
The G-7900 suits
- Surfers, anglers and beachgoers who want tide and moon data at a glance.
- Anyone who wants a bold, sporty digital look.
Look elsewhere if
- Small wrists — it is 50 mm wide and 17.7 mm thick.
- People who want solar or atomic time.
Custom G-7900 builds: what changes
- Our G-7900 build is based on the G-7900A-4 colorway.
- Custom modifications can affect water resistance; confirm a specific piece with us before swimming.
Bezelwright is an independent customizer and is not affiliated with Casio. Specs above describe Casio's stock model.
Custom G-7900 builds (1, from $150)
G-7900
Sources
Figures describe Casio's stock reference model. Independent references are used where Casio's own page could not be read directly, and cross-checked against Casio's published specs.
- G-Central: G-SHOCK G-7900 specifications (independent reference, accessed October 25, 2026)
- Casio G-SHOCK (UK): Are G-SHOCK watches waterproof or water resistant? (official Casio, accessed October 25, 2026)