Created to commemorate Seiko's 140th anniversary, the Marinemaster 300 Limited Edition in deep forest green is a tribute to the brand’s legacy of professional-grade dive watches. Built for saturation diving and everyday reliability, this timepiece represents the pinnacle of Seiko’s mechanical dive watch engineering.

At its core is the in-house Caliber 8L35, a movement developed and assembled at the Shizukuishi Watch Studio in Japan, offering a 50-hour power reserve, hand-winding capability, and daily accuracy rated between +15 to -10 seconds. It’s the same movement trusted in Seiko’s top-end dive watches, built for performance under pressure.

The case—crafted from stainless steel with a one-piece monocoque structure—measures 44.3mm in diameter and 15.4mm thick, providing serious wrist presence and toughness. A sapphire crystal with anti-reflective coating protects the rich green dial, accented by bold Lumibrite hands and indexes for visibility in complete darkness. The unidirectional ceramic bezel adds durability and function, backed by a screw-down crown and 300m water resistance suitable for saturation diving.

Seiko includes an additional silicone strap alongside the metal bracelet with a slide-adjust clasp for quick resizing. The case back is engraved with “LIMITED EDITION,” marking this as a rare collectible within the Marinemaster lineage.

This edition stands out not just for its capability, but for its deep, elegant green colorway—recalling the natural beauty of Japan and Seiko’s roots.

Key Features:

• Movement:

  • Caliber 8L35

  • Automatic with manual winding

  • Power reserve: Approx. 50 hours

  • Accuracy: +15 to -10 seconds per day

  • Jewels: 26

  • Stop-seconds hand function

• Case:

  • Stainless steel with ceramic unidirectional rotating bezel

  • One-piece monocoque case structure

• Crystal: Sapphire crystal with inner anti-reflective coating

• Dial: Green with Lumibrite on hands, indexes, and bezel

• Case Size:

  • Diameter: 44.3mm

  • Thickness: 15.4mm

• Water Resistance: 300m / 1000ft for saturation diving

• Crown: Screw-down

• Clasp: Three-fold clasp with secure lock, push button release, and slide adjuster

• Straps:

  • Stainless steel bracelet

  • Additional silicone strap included

• Other Features:

  • Date display

  • LIMITED EDITION engraved on case back