Casio Pro Trek PRG270-1 vs Seiko 5 Sports GMT SSK001
Casio's timepiece meets Seiko's GMT watch
Quick Verdict
The Casio Pro Trek PRG270-1 ($150–$250) offers Tough Solar Quartz (No Battery Change) precision in the tier below the Seiko 5 Sports GMT SSK001 ($250–$500). The Pro Trek PRG270-1 measures 54.6 × 52.4 × 15mm and is rated 100m (10 ATM). The 5 Sports GMT SSK001 counters with Made in Japan craftsmanship and 100m (10 ATM) water resistance. Both are exceptional watches for their respective tiers.
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Specifications Compared
| Feature | Casio Pro Trek PRG270-1 | Seiko 5 Sports GMT SSK001 |
|---|---|---|
| Price | $150–$250 | $250–$500 |
| Case Size | 54.6 × 52.4 × 15mm | 42.5mm |
| Movement | Tough Solar (Solar Quartz) | Automatic Caliber 4R34 (True GMT) |
| Caliber Type | Tough Solar Quartz (No Battery Change) | Seiko In-House Automatic GMT |
| Power Reserve | Tough Solar (Rechargeable) | 41 Hours |
| Water Resistance | 100m (10 ATM) | 100m (10 ATM) |
| Crystal | Mineral Glass | Hardlex Crystal |
| Case Material | Resin | Stainless Steel |
| Origin | Casio (Japan) | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Casio's design language vs Seiko's approach
The Casio Pro Trek PRG270-1 features a Resin case at 54.6 × 52.4 × 15mm with Mineral Glass protection. The Seiko 5 Sports GMT SSK001 offers Stainless Steel construction at 42.5mm with Hardlex Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Tough Solar (Solar Quartz) vs Automatic Caliber 4R34 (True GMT)
The Pro Trek PRG270-1 runs the Tough Solar (Solar Quartz) (Tough Solar Quartz (No Battery Change), Tough Solar (Rechargeable) power reserve) at standard frequency. The 5 Sports GMT SSK001 uses the Automatic Caliber 4R34 (True GMT) (Seiko In-House Automatic GMT, 41 Hours reserve) at 21,600 vph (3 Hz). The 5 Sports GMT SSK001 offers a longer power reserve.
Wearability & Fit
54.6 × 52.4 × 15mm vs 42.5mm — different wrist presence
At 54.6 × 52.4 × 15mm, the Pro Trek PRG270-1 has a bolder wrist presence compared to the 5 Sports GMT SSK001 at 42.5mm. Water resistance differs: 100m (10 ATM) vs 100m (10 ATM).
Value & Cost of Ownership
Casio sits in the lower tier
The Casio Pro Trek PRG270-1 sits at $150–$250 and the Seiko 5 Sports GMT SSK001 at $250–$500. On the specs that outlast any price: the Pro Trek PRG270-1 uses Mineral Glass with Tough Solar (Rechargeable), against Hardlex Crystal and 41 Hours on the 5 Sports GMT SSK001. Service intervals are typically 5-7 years for both.
Water Resistance
100m (10 ATM) vs 100m (10 ATM)
The Pro Trek PRG270-1 is rated to 100m (10 ATM) while the 5 Sports GMT SSK001 handles 100m (10 ATM). Both offer identical water resistance ratings.
Our Verdict
Casio
Pro Trek PRG270-1
Choose the Casio Pro Trek PRG270-1 if you prioritize Tough Solar Quartz (No Battery Change) engineering, Casio (Japan) craftsmanship, and 100m (10 ATM) water resistance. At $150–$250, it delivers Tough Solar (Solar Quartz) with Tough Solar (Rechargeable) power reserve.
Check Price on AmazonSeiko
5 Sports GMT SSK001
Choose the Seiko 5 Sports GMT SSK001 if you value Seiko In-House Automatic GMT technology, Made in Japan heritage, and 42.5mm proportions. At $250–$500, the Automatic Caliber 4R34 (True GMT) with 41 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Casio Pro Trek PRG270-1 and Seiko 5 Sports GMT SSK001 represent two distinct approaches to fine watchmaking — the Casio bringing Casio (Japan) tradition while Seiko delivers Made in Japan engineering.
Frequently Asked Questions
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How This Page Was Made
Our comparisons are generated from a hand-maintained specification database and reviewed under our editorial standards. We use AI tools to assemble pages from that data. We don’t invent specs: every number traces back to the database, and when we correct an entry, the fix is applied site-wide. As an Amazon Associate, The Horologist earns from qualifying purchases.