San Martin SN0004 Review – The Retro Diver Causing Hype Waves

San Martin has built a reputation for doing vintage divers right — precise machining, thoughtful proportions, and a level of finishing that pushes beyond its price point. The San Martin SN0004 continues that trend.
This upgraded version of San Martin’s “SN0004” series brings together 316L stainless steel, a boxed sapphire crystal, 200 m water resistance, and a milled on-the-fly adjustment clasp, screw pins — features usually reserved for watches several tiers higher.
It’s the brand’s clearest statement yet that a retro-inspired diver doesn’t need to compromise between warmth, refinement, and tool-watch utility.

San Martin SN0004 – Vintage Style Diver

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Design & Case

The San Martin captures that balance perfectly. Measuring 38 mm in diameter, 13 mm thick, and 46 mm lug-to-lug, it feels compact, agile, and true to vintage form. The 20 mm lugs taper down to 16 mm at the clasp, lending the watch comfort and elegance in equal measure.

The 316L stainless-steel case uses horizontal brushing across the mid-case, accented by soft bevels that transition seamlessly into the downturned lugs. No sharp edges, no unfinished surfaces — it’s smooth to the touch, as refined inside as out.

Visually, the design feels layered: a tall, slightly overhanging bezel crowns the muscular midcase, while the domed crystal adds height without visual bulk. The profile remains balanced and proportionally clean, with the female end links ensuring the bracelet drops vertically, keeping the compact footprint intact even on 5-inch wrists.

The screw-down crown, engraved with San Martin’s hexagonal logo, has a fine-threaded sleeve that adds visual depth and functional grip. At 200 m water resistance, it’s a true diver — built solidly, with tactile precision in every screw and seal.

Bezel

San Martin’s bezels are known for excellence, and this one proves why. The 120-click unidirectional bezel is machined with deep, brushed coin-edge teeth — grippy, even when wet or gloved.
The action is tight and authoritative, offering consistent resistance through each click with near-zero back-play. The sound is mechanical, confident, and satisfying — the hallmark of quality.

Capping the assembly is a polished black ceramic insert with engraved beige numerals that complement the lume tone. The glossy finish reflects light beautifully, lending the SN0004GA a touch of elegance without betraying its tool-watch origins.

That careful restraint — functional grip below, mirror polish above — sums up the watch’s entire design philosophy: purposeful, not flashy.

Crystal & Dial

A boxed, slightly domed synthetic sapphire crystal with anti-reflective treatment protects the dial. The crystal’s curvature gives a soft distortion around the edges, adding vintage warmth. From certain angles, the AR layer reflects a faint blue-purple hue, a subtle but premium touch that enhances clarity.

Beneath it lies a matte black dial that balances heritage and harmony. Circular beige lume plots mark each hour, elongated batons at 3, 6, and 9, and a downward-pointing triangle at 12 — all framed by a precise chapter ring where the lollipop seconds hand tracks perfectly.

The San Martin cursive logo replaces the usual hexagonal badge, reinforcing the vintage aesthetic. Text remains minimal — Automatic 200 m printed cleanly above six.

The pencil hands (optional over the “classic” set) are clean, balanced, and easy to read, filled with warm beige lume that glows a bright green in darkness. It’s a color palette that feels organic — black, beige, and gloss all working together to evoke warmth without artifice.

There’s no date window — and that’s deliberate. The result is perfect symmetry, vintage authenticity, and uninterrupted dial flow.

Bracelet & Clasp

The bracelet is one of the San Martin’s standout features. The female end links and sharply downturned lugs give it exceptional comfort, allowing the bracelet to drape naturally. Brushing on the end links matches the case lugs perfectly, creating seamless visual continuity.

Each solid link is secured by screw pins, not push pins, and the articulation is smooth with zero rattle or looseness. It feels premium — refined tolerances and excellent consistency.

At the clasp, San Martin sets a new standard for AliExpress divers: a fully milled, signed clasp with on-the-fly micro-adjustment. A simple internal slider mechanism lets you fine-tune the fit instantly — no tools needed, no awkward trial and error.
It’s practical, durable, and easily one of the best clasps available under $400.

Movement & Caseback

Powering the SN0004GA is the Seiko NH35 automatic — a 24-jewel, 21,600 bph movement with 42 hours of power reserve, hacking, and hand-winding. Known for reliability and easy servicing, it’s the ideal caliber for a modern dive watch.

The screw-down caseback is fluted and sterile, with no engravings — just clean, brushed steel. It’s understated and utilitarian, keeping with the watch’s vintage DNA while enhancing comfort against the wrist.

Lume

As always, San Martin excels here. The C3 Super-LumiNova glows bright, uniform, and long-lasting — vivid green across both hands and indices. It’s even, crisp, and legible for hours after charging, maintaining visibility well into the night.

Summary

The San Martin SN0004 distills everything collectors love about vintage divers — compact case, clean symmetry, tactile bezel, and creamy lume — into a package that feels like a premium tool watch.
With its boxed sapphire, ceramic bezel, on-the-fly clasp, and NH35 engine, this isn’t just a homage — it’s a refinement of history. At around $250, it’s one of the most complete and balanced offerings in San Martin’s lineup.

Elegant enough for daily wear, robust enough for adventure, and executed with precision that belies its price — this is vintage, done right.

Specifications Table