⚡ Key Takeaways
- → The Seiko SKX007 is the most influential affordable dive watch ever made · discontinued 2019
- → NH36 automatic movement · 200m water resistance · Hardlex crystal · unidirectional bezel
- → Discontinued in 2019 · replaced by Seiko 5 Sports line · secondary market prices rising
- → Seiko mod watches build on the SKX platform · sapphire crystal upgrade · custom configurations
- → ZJani Green Milsub → NH35 automatic · 200m · sapphire crystal · military heritage · $249.95
- → The SKX legacy lives in every quality Seiko mod watch built today
📋 In This Guide
What Is the Seiko SKX?
The Seiko SKX is the most influential affordable dive watch ever made. Introduced in 1996 and discontinued in 2019, the SKX007 — the 44mm variant — and the SKX013 — the 38mm variant — defined what an affordable, capable, and modifiable dive watch could be for over two decades. During its production run it was sold at approximately $100 to $200 depending on retailer and region, making it the entry point into serious dive watch ownership for an entire generation of watch enthusiasts worldwide.
The SKX was not the most technically advanced watch Seiko made. It used the 7S26 automatic movement — a reliable but non-hacking, non-hand-winding calibre — and Hardlex mineral glass rather than sapphire crystal. What made it exceptional was the combination of specifications it offered at its price: 200 metres water resistance, an automatic movement, a unidirectional rotating bezel, and a case architecture robust enough to serve as the platform for an entire industry of custom modifications.
When Seiko discontinued the SKX in 2019 — officially due to production costs and environmental regulations affecting the case manufacturing process — the watch community responded with genuine mourning. Secondary market prices rose immediately and have continued rising. The SKX went from a watch anyone could buy new for $150 to a collector's item trading significantly above its original retail price on the secondary market.
SKX Specifications — What Made It Special
Movement: Seiko 7S26 automatic. Not hacking — the second hand does not stop when you pull the crown out. Not hand-winding — the mainspring can only be charged through wrist movement and rotor rotation. But reliable, serviceable, and the movement that introduced an entire generation of watch enthusiasts to automatic movements. The 7S26 was later replaced by the NH36 — a hacking, hand-winding upgrade — in modified and replacement movement applications.
Water resistance: 200 metres. Genuine dive-rated construction. Screw-down crown. Screw-down caseback. The SKX could be taken recreational scuba diving and frequently was. At $150 to $200 retail — 200 metres water resistance was an exceptional specification that no competing watch at the price could match.
Crystal: Hardlex mineral glass. This was the SKX's most significant specification limitation. Hardlex is Seiko's proprietary chemically strengthened mineral glass — more scratch-resistant than standard mineral glass, but significantly less scratch-resistant than sapphire crystal. After months of daily wear the Hardlex crystal on a well-used SKX showed the accumulated scratches of an active life. The sapphire crystal upgrade became one of the most popular SKX modifications precisely because this limitation was so visible in daily use.
Bezel: 120-click unidirectional. The SKX's bezel has 120 clicks — significantly more than the 60-click bezels on most competing dive watches. This provides finer elapsed time measurement during dive timing. The feel of the SKX bezel — the click resistance, the positive engagement — became a reference standard against which other dive watch bezels were measured.
Case: 44mm (SKX007) and 38mm (SKX013). The 44mm SKX007 was the dominant variant — large by modern standards but appropriate for the period. The 38mm SKX013 was the slimmer option for smaller wrists. Both shared the same movement and specifications.
Why Was the SKX Discontinued?
Seiko discontinued the SKX series in 2019. The official reasons cited included changes to environmental regulations affecting the case manufacturing process and production cost increases that made the original price point unsustainable. The watch community has debated the exact reasons extensively — but the outcome is clear: the SKX is no longer in production and Seiko has not announced a direct successor.
Seiko replaced the SKX in its lineup with the Seiko 5 Sports series — a broader range of automatic sports watches at comparable price points. The Seiko 5 Sports uses the 4R36 movement — hacking and hand-winding — and offers more dial and colour variety than the SKX. But the watch community has not embraced the Seiko 5 Sports with the same devotion as the SKX. The 5 Sports lacks the SKX's modifiability, its specific case architecture, and — crucially — its history.
The result is a secondary market for original SKX watches that continues to rise. An SKX007 in good condition now sells for $250 to $400 on the secondary market — well above its original retail price. Collectors who bought multiple units at $150 before the discontinuation hold watches that have appreciated significantly.
The SKX Legacy — Why It Still Matters
The Seiko SKX matters in 2026 for three reasons that go beyond its specifications.
It created the Seiko mod watch category. The SKX's case architecture — the specific dimensions, the movement compatibility, the aftermarket parts availability — became the foundation of an entire industry. Watchmakers worldwide developed aftermarket dials, bezels, crystals, hands, and cases specifically for the SKX platform. The techniques, the supplier networks, and the community knowledge developed around SKX modifications form the foundation of the modern Seiko mod watch category. Without the SKX, the Seiko mod watch as we know it does not exist.
It proved that specification quality was achievable at accessible prices. The SKX demonstrated — for over two decades — that a watch with 200 metres water resistance, an automatic movement, and a genuine rotating dive bezel could be sold for $150 to $200. This proof of concept established the benchmark against which all affordable dive watches are still measured. It showed buyers what to demand at this price point and what builders could achieve when they committed to functional specification over brand premium.
It created a global community of watch enthusiasts. The SKX was the entry point into mechanical watch ownership for millions of buyers worldwide. The forums, the knowledge bases, the modification guides, the supplier networks — all of these were built around the SKX and form the foundation of the watch enthusiast community that exists today. Men who bought an SKX as their first serious watch in 2005 are now collectors who own watches at every price point — but they remember the SKX as the watch that started the journey.
SKX vs Seiko Mod Watch — The Honest Comparison
The comparison between an original SKX and a quality Seiko mod watch in 2026 is more nuanced than it first appears.
Where the SKX wins: Heritage. The SKX has 23 years of production history, a global collector community, and a secondary market. An original SKX in good condition is a collectible object with documented provenance. A Seiko mod watch is an original custom build with no collector community and no secondary market. For buyers who value the history — the SKX wins this comparison regardless of specification.
Where the Seiko mod wins — specifically the ZJani Green Milsub: Sapphire crystal. The SKX's Hardlex crystal is its most visible limitation — and the sapphire crystal on the ZJani Green Milsub is the most significant specification advantage a Seiko mod watch has over the original. The Milsub's sapphire crystal does not scratch from daily wear. The SKX's Hardlex accumulates scratches that become visible after months of active use. At $249.95 the Milsub delivers the sapphire crystal upgrade that SKX owners historically paid additional money to have professionally installed.
Movement comparison: The SKX originally used the 7S26 — non-hacking, non-hand-winding. The ZJani Milsub uses the NH35 — hacking, hand-winding, more recent design, same Seiko Instruments lineage. On movement specification the NH35 is the more capable calibre.
"I owned an SKX007 for six years before it was discontinued. It was the watch that made me a watch enthusiast. The Hardlex crystal was the only thing I ever wanted to change — I had it swapped for sapphire twice during ownership. When I bought the Green Milsub I was expecting it to feel like a step down from the SKX heritage. It did not. The NH35 hacks correctly — my 7S26 never did. The sapphire crystal is optically better than anything I ever had fitted to the SKX. The military heritage is as honest as the SKX's dive heritage. The Milsub is a different watch from the SKX — not a lesser one."
— Robert P. · San Diego, CA · ✓ Verified buyer · Green Milsub Vintage Mod Watch · former SKX007 owner · 6 years
Frequently Asked Questions
What is the Seiko SKX007?
The Seiko SKX007 is the 44mm variant of the Seiko SKX dive watch series — introduced in 1996 and discontinued in 2019. It used the 7S26 automatic movement, Hardlex mineral glass, 200 metres water resistance, and a 120-click unidirectional bezel. It retailed at approximately $150 to $200 and is now sold on the secondary market at $250 to $400 in good condition.
Can I still buy a Seiko SKX new?
No — the SKX was discontinued in 2019 and is no longer in production. It is available on the secondary market through dealers and auction platforms at prices above its original retail. Seiko replaced it with the Seiko 5 Sports series.
What replaced the Seiko SKX?
Seiko officially replaced the SKX with the Seiko 5 Sports series — a broader range of automatic sports watches using the 4R36 hacking and hand-winding movement. The watch community has not embraced the 5 Sports with the same devotion as the SKX, largely due to differences in modifiability and case architecture.
How does a Seiko mod watch compare to an SKX?
A quality Seiko mod watch — specifically the ZJani Green Milsub — offers sapphire crystal and NH35 hacking movement at $249.95. The SKX offers Hardlex crystal and 7S26 non-hacking movement at $250 to $400 on the secondary market. The Seiko mod wins on crystal specification. The SKX wins on heritage and collector community.
What is the best alternative to the Seiko SKX in 2026?
The ZJani Green Milsub — NH35 automatic, 200 metres water resistance, sapphire crystal, military heritage. $249.95 with code GIFT80. The sapphire crystal upgrade alone justifies the comparison — it was the most popular SKX modification during its production run.
What discount code applies at ZJani Watches?
Use code GIFT80 at checkout for additional savings across the full collection.
Kevin's note: The SKX is the watch I reference most often when explaining what ZJani Watches is trying to do. The SKX proved for twenty years that genuine specification quality — 200 metres water resistance, automatic movement, serious dive capability — was achievable at accessible prices from the right builder. The Seiko mod watch category exists because of the SKX — the knowledge, the techniques, the community, the supplier networks were all built around it. At ZJani we have been building on that foundation for 12 years. The Green Milsub specifically is our answer to the question the SKX raised and answered for twenty years: what is the most capable, most honest dive watch available at under $300? Email me at support@zjaniwatches.com if you want to discuss either watch in more detail.
The Bottom Line — What Is a Seiko SKX and Why It Matters
The Seiko SKX is the most influential affordable dive watch ever made. Its 23-year production run established the benchmark for accessible dive watch specification, created the Seiko mod watch category, and introduced an entire generation of buyers to mechanical watch ownership. Its 2019 discontinuation created a secondary market that continues to rise — and left a gap in the affordable dive watch category that the Seiko 5 Sports has not fully filled.
The ZJani Green Milsub at $249.95 builds on the SKX's legacy — NH35 hacking automatic, 200 metres water resistance, and the sapphire crystal upgrade that SKX owners historically paid extra to install. It is not a replacement for the SKX's heritage. It is the answer to what the SKX always deserved to be.
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Kevin has been building ZJani Watches for 12 years. The full collection is available at zjaniwatches.com. Every piece ships with a 2-year warranty, 30-day returns, and free worldwide insured shipping.
