For watch enthusiasts looking for a versatile 39mm automatic GMT watch, the San Martin SN0109G-A brings together classic GMT styling, modern mechanical performance, and practical everyday upgrades.

Powered by the Hangzhou HZ6460 automatic GMT movement, the SN0109 features a central GMT hand, a high-frequency 28,800 vibrations per hour (4Hz) movement, sapphire crystal, 100M water resistance, and an upgraded On-The-Fly adjustable clasp.

With four dial options and balanced 39mm proportions, the San Martin SN0109 GMT Watch is designed for travelers, collectors, and anyone who appreciates a practical mechanical watch with timeless character.

HZ6460 Automatic GMT Movement – A New Upgrade

At the heart of the San Martin SN0109G-A is the HZ6460 automatic mechanical GMT movement.

Operating at 28,800 vibrations per hour (4Hz), the movement delivers a smooth sweeping seconds hand and a refined mechanical experience.

The movement specifications include:

• HZ6460 automatic mechanical movement
• Central GMT hand
• Four-hand display with date
• 28,800 vibrations per hour / 4Hz
• Hacking / stop-second function
• 25 jewels
• Approximately 40 hours of power reserve

The dedicated GMT hand provides an additional time reference, making the SN0109 particularly useful for travelers and people who regularly need to keep track of another time zone.

Classic 39mm GMT Watch Proportions

A major attraction of the SN0109 is its wearable 39mm stainless steel case.

Instead of going oversized, San Martin has kept the proportions balanced enough for everyday wear while still giving the watch a strong wrist presence.

Case Dimensions

• Case Diameter: 39mm
• Lug to Lug: 48.5mm
• Thickness: 12.25mm
• Case Material: Solid 316L Stainless Steel
• Weight: Approximately 146g

These dimensions make the San Martin 39mm GMT watch an attractive option for enthusiasts who prefer a more compact mechanical sports watch.

Multiple Dial Colors for Different Styles

The San Martin SN0109 is available in several dial configurations, giving collectors more freedom to choose a GMT watch that matches their personal style.

Available options include:

• Black Dial
• White Dial
• Dark Blue Dial
• Black-Gold Matte Dial

The different color combinations give the SN0109 noticeably different personalities, ranging from classic and understated to more distinctive and vintage-inspired.

Combined with the recognizable Snowflake-style hands and central GMT hand, the dial maintains excellent readability while preserving the watch's sporty character.

Aluminum GMT Bezel with Classic Character

The SN0109 features an aluminum bezel insert, adding a more traditional character compared with the glossy appearance of ceramic.

For enthusiasts who appreciate vintage-inspired GMT watches, aluminum offers a distinctive visual texture that works particularly well with the SN0109's classic case and dial combinations.

The bezel also makes it easier to reference an additional time zone together with the central GMT hand.

Top Hat Sapphire Crystal with AR Coating

Protecting the dial is a Top Hat sapphire crystal with anti-reflective coating.

Sapphire offers excellent scratch resistance for everyday use, while the AR coating helps reduce unwanted reflections and improves dial visibility under different lighting conditions.

The raised Top Hat profile also adds extra visual character, complementing the watch's classic GMT-inspired design.

BGW-X1 Blue Lume for Nighttime Visibility

Good legibility is important for any sports or travel watch.

The San Martin SN0109 uses BGW-X1 blue luminous material on the hands and hour markers, creating a bright blue glow in low-light conditions.

Together with the contrasting hands and applied markers, the lume helps keep the watch easy to read during nighttime travel and everyday use.

Upgraded On-The-Fly Adjustable Clasp

One of the most practical features of the SN0109 is its On-The-Fly (OTF) adjustable clasp.

The solid 316L stainless steel bracelet measures 20mm at the lugs and tapers to 16mm, giving the watch a balanced and comfortable profile.

More importantly, the OTF clasp allows quick micro-adjustments without requiring tools.

This is particularly useful when your wrist expands or contracts due to temperature changes, travel, exercise, or long periods of wear.

Bracelet Details

• Solid 316L stainless steel construction
• 20mm tapering to 16mm
• Band length: 190mm / 7.5in
• On-The-Fly adjustable clasp
• San Martin hexagon logo

For everyday comfort, the OTF adjustable clasp is one of the most useful upgrades on the San Martin SN0109.

100M Water Resistance for Everyday Adventures

The SN0109 is equipped with a screw-down crown featuring San Martin's 3D hexagonal logo, along with a screw-down case back.

The watch provides 10Bar / 100 meters of water resistance, giving it the versatility expected from a modern sports watch.

Whether you're traveling, commuting, heading to the office, or enjoying a weekend away, the SN0109 is designed to transition easily between different environments.

San Martin SN0109G-A Specifications

Brand: San Martin
Model: SN0109G-A

Movement

• HZ6460 Automatic Mechanical Movement
• Central GMT Hand
• Four Hands + Date
• 28,800 Vibrations Per Hour / 4Hz
• Stop-Second Function
• 25 Jewels
• Approximately 40-Hour Power Reserve

Case

• Solid 316L Stainless Steel
• Diameter: 39mm
• Lug to Lug: 48.5mm
• Thickness: 12.25mm

Crystal

• Top Hat Sapphire Crystal
• Anti-Reflective Coating

Bezel

• Aluminum Bezel Insert

Dial

• Black
• White
• Dark Blue
• Black-Gold Matte

Hands & Lume

• Snowflake Hands
• Central GMT Hand
• BGW-X1 Blue Lume on Hands and Markers

Crown

• Screw-down Crown
• 3D San Martin Hexagonal Logo

Case Back

• Screw-down Case Back
• Brushed Finish

Bracelet

• Solid 316L Stainless Steel
• 20mm tapering to 16mm
• Length: 190mm / 7.5in

Clasp

• On-The-Fly Adjustable Clasp
• San Martin Hexagon Logo

Water Resistance

• 10Bar / 100 Meters

Weight

• Approximately 146g

Warranty

• 2 Years

Why Choose the San Martin SN0109 GMT Watch?

The San Martin SN0109G-A offers a compelling combination of classic GMT design and modern mechanical specifications.

Its 39mm stainless steel case provides versatile proportions, while the HZ6460 4Hz automatic GMT movement adds practical multi-time-zone functionality. The Top Hat sapphire crystal, BGW-X1 lume, 100M water resistance, and upgraded OTF adjustable clasp further improve its usability as an everyday mechanical watch.

Key highlights include:

• 39mm versatile case size
• HZ6460 4Hz automatic GMT movement
• Central GMT hand and date display
• 40-hour power reserve
• Top Hat sapphire crystal with AR coating
• Multiple dial color options
• BGW-X1 blue lume
• 100M water resistance
• On-The-Fly adjustable clasp
• Solid 316L stainless steel construction

For travelers, GMT enthusiasts, and collectors looking for a 39mm automatic mechanical GMT watch, the San Martin SN0109 offers a strong balance of functionality, comfort, and classic design.