G-Shock comparison
Casio G-Shock GA-2100-1A1 'CasiOak' vs Casio G-Shock GA-100-1A1
Verdict. Today the Casio G-Shock GA-100-1A1 (GA-100-1A1) is the better value by our formula: Value Score 83 vs 73, with 49 spec points at $83.60. The other watch costs $24.35 more. Prices as of November 3, 2026, 18:15 UTC.
Side by side
Casio G-Shock GA-2100-1A1 'CasiOak' vs Casio G-Shock GA-100-1A1: specs and price
| Spec |  Casio G-Shock GA-2100-1A1 'CasiOak' GA-2100-1A1 |  Casio G-Shock GA-100-1A1 GA-100-1A1 |
|---|---|---|
| Price on Amazon today | $107.95 | $83.60 |
| Value Score (within type) | 73 | 83 |
| Spec points | 49 | 49 |
| Spec points per $100 | 45.4 | 58.6 |
| Movement | Digital quartz (analog-digital) | Digital quartz (analog-digital) |
| Power reserve | — | — |
| Crystal | Mineral | Mineral |
| Water resistance | 200 m | 200 m |
| Screw-down crown | No | No |
| Case diameter | 45.4 mm | 51.2 mm |
| Lug-to-lug | 48.5 mm | 55 mm |
| Thickness | 11.8 mm | 16.9 mm |
| Lug width | — | — |
| Fits wrist from | ≥ 17.5 cm (6.9″) | ≥ 19.8 cm (7.8″) |
| Strap / bracelet | Resin | Resin |
| Made in | — | — |
| Amazon sales rank | #403 | #37 |
FAQ
Questions about the Casio G-Shock GA-2100-1A1 'CasiOak' and the Casio G-Shock GA-100-1A1
Which is cheaper on Amazon today?
As of November 3, 2026, 18:15 UTC, the Casio G-Shock GA-2100-1A1 'CasiOak' (GA-2100-1A1) is $107.95 and the Casio G-Shock GA-100-1A1 (GA-100-1A1) is $83.60; the difference is $24.35. Amazon's price at checkout applies.
Context
Where both sit among G-Shock watches
| # | Watch | Movement | Crystal | Water res. | Case diameter × lug-to-lug | Fits wrist | Spec pts | Price | Value Score | Buy |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | Digital quartz | Mineral | 200 m | 43.2 × 48.5 mm | ≥ 17.5 cm (6.9″) | 49 | $57.00 | 100 | Amazon |
| 2 |  | Digital quartz | Mineral | 200 m | 51.2 × 55 mm | ≥ 19.8 cm (7.8″) | 49 | $70.98 | 90 | Amazon |
| 3 | | Digital quartz (analog-digital) | Mineral | 200 m | 51.2 × 55 mm | ≥ 19.8 cm (7.8″) | 49 | $83.60 | 83 | Amazon |
| 4 |  | Digital quartz | Mineral | 200 m | 42.8 × 48.9 mm | ≥ 17.6 cm (6.9″) | 49 | $83.99 | 82 | Amazon |
| 5 |  | Digital quartz (analog-digital) | Mineral | 200 m | 53.4 × 57.5 mm | ≥ 20.7 cm (8.1″) | 49 | $101.88third-party | 75 | Amazon |
| 6 |  | Solar digital | Mineral | 200 m | 43.2 × 46.7 mm | ≥ 16.8 cm (6.6″) | 55 | $139.32 | 68 | Amazon |
| 7 | | Digital quartz (analog-digital) | Mineral | 200 m | 45.4 × 48.5 mm | ≥ 17.5 cm (6.9″) | 49 | $107.95third-partyships later | 73 | Amazon |
| 8 |  | Digital quartz (analog-digital) | Mineral | 200 m | 55.3 × 56.2 mm | ≥ 20.2 cm (8.0″) | 49 | $244.44ships later | 48 | Amazon |
Amazon.com prices as of November 3, 2026, 18:15 UTC — details. third-party = sold by a marketplace seller, not Amazon (warranty may differ); ships later = not in stock today, never crowned best value.