Seiko 5 Sports GMT SSK001 vs Tissot Seastar 1000 Automatic
Seiko's GMT watch meets Tissot's diver
Quick Verdict
The Seiko 5 Sports GMT SSK001 ($250–$500) offers Seiko In-House Automatic GMT precision in the tier below the Tissot Seastar 1000 Automatic ($500–$1,000). The 5 Sports GMT SSK001 measures 42.5mm and is rated 100m (10 ATM). The Seastar 1000 Automatic counters with Swiss Made craftsmanship and 300m (30 ATM) water resistance. Both are exceptional watches for their respective tiers.
Transparency — We earn a small commission on purchases made through our Amazon links. This doesn't affect our editorial independence.
Specifications Compared
| Feature | Seiko 5 Sports GMT SSK001 | Tissot Seastar 1000 Automatic |
|---|---|---|
| Price | $250–$500 | $500–$1,000 |
| Case Size | 42.5mm | 40mm |
| Movement | Automatic Caliber 4R34 (True GMT) | Automatic Powermatic 80 (Caliber 80.111) |
| Caliber Type | Seiko In-House Automatic GMT | ETA/Tissot Automatic |
| Power Reserve | 41 Hours | 80 Hours |
| Water Resistance | 100m (10 ATM) | 300m (30 ATM) |
| Crystal | Hardlex Crystal | Sapphire Crystal |
| Case Material | Stainless Steel | Stainless Steel |
| Origin | Made in Japan | Swiss Made |
Category-by-Category Analysis
Design & Aesthetics
Seiko's design language vs Tissot's approach
The Seiko 5 Sports GMT SSK001 features a Stainless Steel case at 42.5mm with Hardlex Crystal protection. The Tissot Seastar 1000 Automatic offers Stainless Steel construction at 40mm with Sapphire Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Automatic Caliber 4R34 (True GMT) vs Automatic Powermatic 80 (Caliber 80.111)
The 5 Sports GMT SSK001 runs the Automatic Caliber 4R34 (True GMT) (Seiko In-House Automatic GMT, 41 Hours power reserve) at 21,600 vph (3 Hz) frequency. The Seastar 1000 Automatic uses the Automatic Powermatic 80 (Caliber 80.111) (ETA/Tissot Automatic, 80 Hours reserve) at 21,600 vph (3 Hz). The Seastar 1000 Automatic offers a longer power reserve.
Wearability & Fit
42.5mm vs 40mm — different wrist presence
At 42.5mm, the 5 Sports GMT SSK001 has a bolder wrist presence compared to the Seastar 1000 Automatic at 40mm. Water resistance differs: 100m (10 ATM) vs 300m (30 ATM).
Value & Cost of Ownership
Seiko sits in the lower tier
The Seiko 5 Sports GMT SSK001 sits at $250–$500 and the Tissot Seastar 1000 Automatic at $500–$1,000. On the specs that outlast any price: the 5 Sports GMT SSK001 uses Hardlex Crystal with 41 Hours, against Sapphire Crystal and 80 Hours on the Seastar 1000 Automatic. Service intervals are typically 5-7 years for both.
Water Resistance
100m (10 ATM) vs 300m (30 ATM)
The 5 Sports GMT SSK001 is rated to 100m (10 ATM) while the Seastar 1000 Automatic handles 300m (30 ATM). The Seastar 1000 Automatic offers superior water resistance.
Our Verdict
Seiko
5 Sports GMT SSK001
Choose the Seiko 5 Sports GMT SSK001 if you prioritize Seiko In-House Automatic GMT engineering, Made in Japan craftsmanship, and 100m (10 ATM) water resistance. At $250–$500, it delivers Automatic Caliber 4R34 (True GMT) with 41 Hours power reserve.
Check Price on AmazonTissot
Seastar 1000 Automatic
Choose the Tissot Seastar 1000 Automatic if you value ETA/Tissot Automatic technology, Swiss Made heritage, and 40mm proportions. At $500–$1,000, the Automatic Powermatic 80 (Caliber 80.111) with 80 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Seiko 5 Sports GMT SSK001 and Tissot Seastar 1000 Automatic represent two distinct approaches to fine watchmaking — the Seiko bringing Made in Japan tradition while Tissot delivers Swiss Made engineering.
Frequently Asked Questions
More Comparisons
Tag Heuer Carrera Chronograph vs Seiko 5 Sports GMT SSK001
Tag Heuer's chronograph meets Seiko's GMT watch
Tag Heuer Carrera Chronograph vs Tissot Seastar 1000 Automatic
Tag Heuer's chronograph meets Tissot's diver
Tissot PRX Powermatic 80 vs Seiko 5 Sports GMT SSK001
Tissot's timepiece meets Seiko's GMT watch
Explore These Watches
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.