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Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) vs Seiko Prospex "Turtle"
Omega's chronograph meets Seiko's diver
Quick Verdict
The Seiko Prospex "Turtle" ($500–$1,000) delivers In-House Automatic Manufacture technology in the tier below the Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) ($10,000–$25,000). The Prospex "Turtle" measures 45mm and is rated 200m (20 ATM) Diver. The Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) justifies its premium with Swiss Made heritage and Omega Co-Axial Master Chronometer calibre 8806, automatic, METAS certified. Both represent excellent choices in the luxury watch category.
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Omega
Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500)
$10,000–$25,000
Specifications Compared
| Feature | Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) | Seiko Prospex "Turtle" |
|---|---|---|
| Price | $10,000–$25,000 | $500–$1,000 |
| Case Size | 42mm, 13.56mm thick, 49.9mm lug to lug, 20mm lugs | 45mm |
| Movement | Omega Co-Axial Master Chronometer calibre 8806, automatic, METAS certified | Automatic Caliber 4R36 |
| Caliber Type | Omega 8806, Master Chronometer | In-House Automatic Manufacture |
| Power Reserve | About 55 hours | 41 Hours |
| Water Resistance | 300m (30 bar) | 200m (20 ATM) Diver |
| Crystal | Domed sapphire, anti-reflective both sides | Sapphire Crystal |
| Case Material | Brushed grade 2 titanium; crown, bezel ring and helium escape valve in 18k Sedna gold; bezel base in tantalum; screw-in crown; sapphire caseback with the Seahorse | Stainless Steel |
| Origin | Swiss Made | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Omega's design language vs Seiko's approach
The Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) features a Brushed grade 2 titanium; crown, bezel ring and helium escape valve in 18k Sedna gold; bezel base in tantalum; screw-in crown; sapphire caseback with the Seahorse case at 42mm, 13.56mm thick, 49.9mm lug to lug, 20mm lugs with Domed sapphire, anti-reflective both sides protection. The Seiko Prospex "Turtle" offers Stainless Steel construction at 45mm with Sapphire Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Omega Co-Axial Master Chronometer calibre 8806, automatic, METAS certified vs Automatic Caliber 4R36
The Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) runs the Omega Co-Axial Master Chronometer calibre 8806, automatic, METAS certified (Omega 8806, Master Chronometer, About 55 hours power reserve) at standard frequency. The Prospex "Turtle" uses the Automatic Caliber 4R36 (In-House Automatic Manufacture, 41 Hours reserve) at 21,600 vph (3 Hz). The Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) edges ahead on power reserve.
Wearability & Fit
42mm, 13.56mm thick, 49.9mm lug to lug, 20mm lugs vs 45mm — different wrist presence
At 42mm, 13.56mm thick, 49.9mm lug to lug, 20mm lugs, the Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) wears more compactly on smaller wrists compared to the Prospex "Turtle" at 45mm. Water resistance differs: 300m (30 bar) vs 200m (20 ATM) Diver.
Value & Cost of Ownership
Seiko sits in the lower tier
The Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) sits at $10,000–$25,000 and the Seiko Prospex "Turtle" at $500–$1,000. On the specs that outlast any price: the Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) uses Domed sapphire, anti-reflective both sides with About 55 hours, against Sapphire Crystal and 41 Hours on the Prospex "Turtle". Service intervals are typically 5-7 years for both.
Water Resistance
300m (30 bar) vs 200m (20 ATM) Diver
The Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) is rated to 300m (30 bar) while the Prospex "Turtle" handles 200m (20 ATM) Diver. The Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) is better suited for water activities.
Our Verdict
Omega
Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500)
Choose the Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) if you prioritize Omega 8806, Master Chronometer engineering, Swiss Made craftsmanship, and 300m (30 bar) water resistance. At $10,000–$25,000, it delivers Omega Co-Axial Master Chronometer calibre 8806, automatic, METAS certified with About 55 hours power reserve.
Check Price on AmazonSeiko
Prospex "Turtle"
Choose the Seiko Prospex "Turtle" if you value In-House Automatic Manufacture technology, Made in Japan heritage, and 45mm proportions. At $500–$1,000, the Automatic Caliber 4R36 with 41 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm 210.60.42.20.99.001 (titanium, tantalum and Sedna gold, limited to 2,500) and Seiko Prospex "Turtle" represent two distinct approaches to fine watchmaking — the Omega bringing Swiss Made 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.