San Martin SN0136 GMT Diver — 39mm NH34, Enamel Dial, 120-Click Ceramic Bezel, 200m

San Martin SN0136 GMT Diver — 39mm NH34, Enamel Dial, 120-Click Ceramic Bezel, 200m

The San Martin SN0136-G is a 39mm GMT automatic dive watch combining two specifications that are genuinely rare at the same price point: a dedicated NH34 GMT movement and enamel sunray dial construction. The enamel sunray finish — a lacquered, multi-layer dial surface that produces a depth and colour shift under changing light — is significantly more complex to produce than standard printed or applied dials and is typically found on watches at higher price points.

Powered by the Seiko NH34 dedicated GMT caliber with an independently adjustable GMT hand for second time zone tracking. 120-click unidirectional ceramic bezel, dual lume system (BGW-X1 blue-white on hands and markers, C3 green on chapter ring), GS Crafts GMT four-hand set, 316L H-link stainless steel bracelet with fly adjustable clasp, 200m water resistance.

Available in enamel green, enamel blue, enamel black and enamel brown — each on either the H-link bracelet or a coloured nylon strap.

Key Specifications

Variants — Four Enamel Dial Colours

Enamel green / bracelet or nylon: A deep sunray green — the most distinctive of the four colourways and the one that most clearly references vintage professional dive watch design. The enamel finish creates a surface that shifts from deep emerald under direct light to a darker, more olive-influenced tone in shadow. The green enamel against the ceramic bezel (available in matching coloured bezel depending on configuration) creates a cohesive sport watch palette.

Enamel blue / bracelet or nylon: A rich navy-to-sapphire sunray blue that transitions from darker at the edges to slightly lighter at the centre. The blue is the most conventionally versatile of the four — blue dials are the most broadly accepted GMT watch colour in the collector market. The BGW-X1 blue-white lume on the blue dial creates a tonal harmony in daylight while providing a clearly distinguishable contrast in darkness.

Enamel black / bracelet or nylon: Matte-to-gloss black sunray — the highest contrast configuration for the BGW-X1 markers and the red GMT hand. Black and red is a classic GMT colour combination; against the black enamel the red GMT arrow is immediately readable at a glance.

Enamel brown / bracelet or nylon: A warm chocolate-to-caramel sunray tone — the warmest and most unusual of the four, with the brown shifting from deep tobacco at the outer edges to a lighter amber at the centre. Brown dial GMT watches are more common in the collector category than in the mainstream market and signal specific vintage and field watch appreciation.

Enamel Sunray Dial — What It Is and Why It Matters

The enamel sunray finish is produced by applying multiple layers of lacquer to the base dial plate, each layer cured and polished before the next is applied. The final surface has a physical depth that a single-coat paint or printed dial cannot replicate. The sunray pattern — fine radiating lines that catch light from different directions as the wrist moves — is applied through the lacquer layers, creating a dial that appears to change colour and intensity under different lighting conditions.

In practical terms: an enamel sunray dial in direct sunlight looks different from the same dial under office fluorescent lighting, which looks different again at dusk. This variability is what collectors describe as “depth” and is the defining characteristic of why enamel dials are specified on more expensive watches. San Martin’s application of enamel sunray at this price tier is one of the primary reasons the SN0136 has attracted attention in watch communities.

Movement — Seiko NH34 GMT

The NH34 is Seiko’s dedicated GMT automatic caliber — purpose-built for GMT function rather than a standard movement with an added GMT module. The independent GMT architecture keeps the 13.5mm total case thickness achievable without the additional height a modular GMT would add.

Key functions:

Independent 24-hour GMT hand: completes one revolution per 24 hours, pointing to the 24-hour scale on the ceramic bezel insert or the inner chapter ring to display the home time zone continuously.

Hour-jump setting: pull the crown to position 1 and turn to advance the main hour hand in one-hour increments without stopping the running movement or disturbing the GMT hand. When crossing time zones, advance the main hour by the offset while the GMT hand continues tracking home time — the cleanest practical GMT adjustment method.

Hacking: seconds stop when the crown is pulled to position 2 for precise synchronisation.

Hand-winding: via the crown in position 2.

Date at 3 o’clock: quick-set via crown position 1.

GS Crafts GMT Handset and Dual Lume

The GS Crafts GMT four-hand set uses the same hand profile manufacturer as the SN0138 snowflake hands — GS Crafts is a specialist Chinese hand maker whose finishing quality is consistently noted as above average in watch community reviews. The four hands are the main hour, minute, seconds and the red-tipped GMT arrow — the red tip provides immediate visual separation of the GMT hand from the other three.

The dual lume system applies BGW-X1 blue-white to the hands and hour markers — the primary time display elements — and SLN C3 green to the chapter ring graduation track. In darkness: the time display glows blue-white, the chapter ring glows green. The two colours create a dual-zone lume field where scale and time are distinguishable by colour rather than requiring position interpretation.

120-Click Ceramic Bezel

The 120-click unidirectional ceramic bezel provides 30-second increment resolution — useful for dive timing where precision beyond 60-second intervals matters. The ceramic insert resists scratching and fading significantly better than aluminium. The engraved numerals — cut into the ceramic rather than printed — remain readable long after the surface of a printed bezel would have degraded.

The bezel rotates in one direction only (counterclockwise) — the safety specification for dive timing. The crown guard at the 3-4 o’clock position protects the crown from impact during diving.

H-Link Bracelet and Fly Adjustable Clasp

The H-link bracelet construction — wider centre links flanked by two narrower outer links at each position — creates a more formal, structured bracelet profile than a standard 7-link construction. The link width tapers from 20mm at the lug to 18mm at the clasp, producing a natural wrist curve. At approximately 160.5g on bracelet the SN0136 has a solid, present feel appropriate for a sport dive watch.

The fly adjustable clasp allows tool-free micro-adjustment on the wrist — press the button and extend or contract in 2mm increments. The clasp face carries the San Martin hexagon logo, consistent with the signed crown hardware.

Who Is the San Martin SN0136 For?

The SN0136 is built for:

• GMT buyers who specifically want an NH34 dedicated GMT caliber in a dive watch case at 39mm — the compact case size is one of the SN0136’s primary differentiators from 40–42mm GMT divers
• Enamel sunray dial collectors who want the dial depth and light variability not available on standard printed or applied dials at this price
• Those who want the dual BGW-X1 + C3 dual-zone lume system as a functional and aesthetic feature
• Divers who need 200m water resistance alongside GMT functionality

How It Compares

vs. Baltany S6074 Pepsi GMT — The Baltany S6074 uses NH34 with a rotating blue-red pepsi bezel at 39mm. The SN0136 has the enamel dial and 200m vs the S6074’s 200m and jubilee bracelet. Both use NH34 — compare enamel dial vs standard dial and bezel colour preference.

vs. Baltany S6073 Retro GMT — The S6073 uses NH34 with a fixed bezel and orange GMT hand, cream or black dial. The SN0136 is the rotating bezel, enamel dial, diver-specification alternative.

vs. San Martin SN0121TD Titanium GMT — The SN0121TD offers Grade 5 titanium construction and 300m. The SN0136 offers the enamel dial and NH34 GMT function. Choose by material (titanium vs steel) and whether GMT or pure dive spec is the priority.

vs. San Martin SN0129 Desert GMT — The SN0129 takes a field-watch-inspired GMT direction with earth-tone dials. The SN0136 is the dive-spec GMT alternative with the enamel sunray finish.

vs. San Martin Titanium GMT Diver — The San Martin Titanium GMT offers titanium construction with GMT at 39mm. Compare material preference directly.

More from Jewelry Addicts

Exploring San Martin GMT watches and enamel dial automatics:

• San Martin Watches — Full Collection — all San Martin models at Jewelry Addicts
• Baltany S6074 Pepsi GMT — Baltany NH34 GMT for direct comparison
• San Martin SN0129 Desert GMT — earth-tone GMT alternative
• San Martin SN0121TD Titanium Diver — titanium 300m dive watch
• Baltany Movements Explained — NH34 GMT function explained in detail