Comparison · Reviewed
GA-2100 vs GM-2100: Resin or Steel-Bezel CasiOak?
Verdict
Choose the GA-2100 for the lightest, cheapest CasiOak at 51 g; choose the GM-2100 for a stainless steel bezel and a dressier look at 72 g, with the same module, battery and 200 m rating.
GA-2100 vs GM-2100 side by side
Casio's specifications for the stock GA-2100-1A1 and GM-2100-1A.
| GA-2100 | GM-2100 | |
|---|---|---|
| Display | Analog-digital | Analog-digital |
| Shape | Octagonal | Octagonal, stainless steel bezel |
| Case size (L × W × H) | 48.5 × 45.4 × 11.8 mm | 49.3 × 44.4 × 11.8 mm |
| Thickness | 11.8 mm | 11.8 mm |
| Weight | 51 g (1.8 oz) | 72 g (2.5 oz) |
| Case | Carbon fiber–reinforced resin (Carbon Core Guard) | Resin case with stainless steel bezel |
| Water resistance | 200 m / 20 bar | 200 m / 20 bar |
| Power | Battery: SR726W × 2, about 3 years | Battery: SR726W × 2, about 3 years |
| Tough Solar | No | No |
| Multi-Band 6 | No | No |
| Bluetooth | No | No |
| Module | 5611 | 5611 |
| Launched | 2019 | 2021 |
| Casio U.S. list price | $110 | $220 |
Which one should you buy?
Choose the GA-2100 if
- You want the lightest octagon (51 g).
- You want bold resin colorways and the biggest custom selection.
- You want the lower list price ($110 vs $220).
Choose the GM-2100 if
- You want real metal and a polished, hairline-finished bezel.
- You want a G-SHOCK that works with smarter outfits.
- You don't mind 21 g of extra weight.
What the GA-2100 and GM-2100 have in common
- Same module 5611 and functions.
- Same three-year SR726W × 2 battery.
- Same 11.8 mm thickness and 200 m water resistance.
GA-2100 vs GM-2100: questions
Is the GM-2100 full metal?
No. The stock GM-2100 has a steel bezel over a resin case and band. Casio's full-metal octagon is the GM-B2100.
Does the GM-2100 scratch?
Polished steel shows fine scratches over time, while resin hides them. That is a style trade-off rather than a durability problem.
Not sure? Send us your wrist size and how you'll wear it; a person replies.
Sources
- Casio: GA-2100-1A specifications (official Casio, accessed October 25, 2026)
- Casio G-SHOCK (U.S.): GA2100: Slim & Tough Analog-Digital Watches (official Casio, accessed October 25, 2026)
- Casio: GA-2100K-1A specifications (battery, band size) (official Casio, accessed October 25, 2026)
- G-Central: G-SHOCK GA-2100 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)
- Casio (U.S.): GA-B2100-1A specifications (official Casio, accessed October 25, 2026)
- Casio (U.S.): GM-2100-1A steel bezel watch (official Casio, accessed October 25, 2026)
- Casio (Canada): GM-2100-1A specifications (battery) (official Casio, accessed October 25, 2026)
- G-Central: G-SHOCK GM-2100 specifications (independent reference, accessed October 25, 2026)
- G-Central: G-SHOCK GM-B2100 (full metal) specifications (independent reference, accessed October 25, 2026)