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# Seiko Turns the New Marinemaster Green for Its Latest Save the Ocean Edition
- URL: https://www.itsabouttime.email/seiko-turns-the-new-marinemaster-green-for-its-latest-save-the-ocean-edition/
- Published: 2026-10-14T12:59:47.000Z
- Updated: 2026-10-14T12:59:47.000Z
- Author: Vuk Radic
- Tags: News

The Marinemaster is Seiko’s top mechanical dive watch, and the current generation is only six months old. Seiko had already redesigned it two years earlier, so the March update came faster than anyone expected. It kept the 1968 design and the 42.6mm case and changed four things: a ceramic bezel insert, the date moved to 3:00, a tool-free micro-adjusting clasp, and the calibre 8L45\. Those changes made it the best diver Seiko sells, if that's what floats your boat. The HBF003 is the first special edition built on that version, with a green sunray dial in place of the black grained one and it's part of Seiko's Save the Ocean effort that funds multiple ocean preservation and exploration efforts.

![](https://storage.ghost.io/c/98/15/981552fd-1b67-4d3c-8ad7-fc38a52bf9fb/content/images/2026/10/Seiko-Mairnemaster-HBF003-2.png)

The steel case is unchanged from the standard HBF001\. That means that it's made out of stainless steel and measures 42.6mm wide, a massive 14.1mm thick and has a lug-to-lug of 49.3mm. I know this is a dive watch that's actually intended to be used as a tool, but that thickness is hard to justify. On top is a double domed sapphire crystal, surrounded by a unidirectional bezel that has a black ceramic insert with the classic 60 minute scale. The caseback is engraved “Limited Edition” with the individual number, the only physical sign on the case that this isn’t the regular model. Water resistance is 300 meters. 

![](https://storage.ghost.io/c/98/15/981552fd-1b67-4d3c-8ad7-fc38a52bf9fb/content/images/2026/10/Seiko-Mairnemaster-HBF003-3.png)

Seiko claims that the green of the dial is inspired by mangrove forests, the coastal trees that grow between the sea and fresh water and protect shorelines from erosion, and it goes from near-black to bright green depending on the light. The seconds hand is pink gold-tone. Everything else on the dial matches the HBF001, including the date at 3:00\. 

![](https://storage.ghost.io/c/98/15/981552fd-1b67-4d3c-8ad7-fc38a52bf9fb/content/images/2026/10/Seiko-Mairnemaster-HBF003-4.jpg)

The calibre 8L45 is an automatic movement based on the Grand Seiko 9S65 architecture, and it beats at 4Hz, with a 72-hour power reserve, and a rated accuracy of +10 to -5 seconds per day. The steel bracelet’s clasp adjusts by 16mm in eight 2mm steps without tools.

The Seiko Prospex Marinemaster 1968 Heritage Save the Ocean Limited Edition HBF003 is limited to 900 pieces. As for pricing, it's only been published on the UK website for now, even though the watch will be available worldwide, and it's set at £3,300 or about €3,900\. That's a lot of money. See more [on the Seiko website](https://www.seikowatches.com/global-en/products/prospex/hbf003j1?ref=itsabouttime.email).