Seiko Prospex SPB381J1 — Automatic GMT Diver's Watch

The Seiko Prospex SPB381J1 is a professional automatic GMT diver's watch with a green dial — the direct green dial sibling of the SPB383J1, sharing the same 6R54 calibre, 42mm case, 12.9mm slim profile, ceramic bezel, sapphire crystal, and Diver's 200M specification. The green dial gives the SPB381J1 an immediate ocean-connected, collector-coded character that the black dial SPB383J1 does not share — and in the context of a 6R54 GMT diver's watch with a ceramic bezel, the green is a rare and distinctive colour choice at this specification level.

Powered by the 6R54 calibre with a 72-hour power reserve, hand-winding capability, and +25/-15 seconds per day accuracy, the SPB381J1 delivers a genuine mechanical GMT complication in a Diver's 200M case at 42mm. The GMT hand is independently settable for a second time zone; the 24-hour hand distinguishes AM/PM at a glance. The sapphire crystal protects the green dial, Lumibrite on the hands and hour markers ensures readability at depth and in low light, and the screw-down crown reinforces the water seal. The silver stainless steel bracelet and hard-coated case complete a specification built for both serious diving and practical travel.

Key Features

• Seiko 6R54 automatic movement with manual winding — Seiko's current Prospex GMT calibre in a Diver's 200M case
• GMT hand — independently settable for a second time zone reference
• 24-hour hand — AM/PM and time zone distinction at a glance
• Approx. 72-hour (3-day) power reserve — reliable performance through a long weekend without wearing
• Accuracy: +25/-15 seconds per day (5°C–35°C) — dependable automatic timekeeping
• Diver's 200M water resistance — built to professional diving standards
• Green dial with baton markers — ocean-connected, collector-coded colourway rare at this specification level
• Lumibrite on hands and hour markers — superior legibility in low light and underwater conditions
• Black ceramic unidirectional rotating bezel — scratch-resistant, precise, and purpose-built for dive timing
• Sapphire crystal — premium scratch resistance and superior optical clarity
• 42mm silver stainless steel case with hard coating — professional GMT diver's proportions at 12.9mm slim profile
• Screw-down crown — water integrity protection for diving use
• Date display — everyday practicality built in
• Silver stainless steel bracelet — durable, comfortable, and corrosion-resistant

Why You'll Love It

The SPB381J1 is the 6R54 GMT diver for those who want the green dial — and among the 6R54-powered Prospex GMT divers, the green is the rarest and most collector-oriented colour choice. Green dials on professional dive watches have a specific cultural resonance, connecting the watch directly to the ocean it was built for, and the combination of a green dial, ceramic bezel, and 6R54 GMT calibre in a 42mm Diver's 200M case is a genuinely distinctive specification package. The 12.9mm slim profile makes it one of the most comfortable-wearing GMT divers available, the sapphire crystal keeps it pristine through active daily use, and the 72-hour reserve handles any extended weekend. A GMT diver that earns its colour choice with substance.

SPB381J1 vs SPB383J1 — Green or Black Dial?

Both models share identical specifications — the same 6R54 calibre, 42mm silver stainless case with hard coating, 12.9mm depth, Diver's 200M water resistance, ceramic unidirectional bezel, sapphire crystal, screw-down crown, Lumibrite, date display, and 72-hour power reserve. The difference is entirely in the dial colour. The SPB381J1 has a green dial — the more distinctive, ocean-connected, and collector-coded choice. The SPB383J1 has a black dial — the more understated and universally wearable choice. Same 6R54 GMT diver specification, two completely different visual characters.

The Seiko Prospex Story

Prospex is a combination of the words "Professional" and "Specifications." Seiko Prospex timepieces are designed to be practical, reliable, and durable — built to meet the high standards required in extreme environments for sports lovers and adventure seekers alike. The story begins in 1881, when Kintaro Hattori founded a clock and watch shop in Ginza, Tokyo — the business that would become the Seiko of today. Since 1965, when Seiko created Japan's first diver's watch, the Prospex dive line has stood for underwater precision and reliability. The SPB381J1 carries that legacy forward in the most distinctive dial colour in the 6R54 GMT diver lineup.

Backed by Seiko's official warranty. Authentic Seiko Prospex watch, sold by authorised retailer City Chain Singapore.

Also available: black dial GMT diver — SPB383J1, 1968 Heritage green dial — HBC001J1, 1968 Heritage black dial — HBC002J1. Explore the full Seiko Prospex Collection or browse all Seiko watches at City Chain Singapore.