Looking Back at One of Seiko’s Most Iconic Divers

Seiko Marinemaster 300 SBDX001 / Credit: WatchReviewBlog

Seiko’s made a lot of divers, and there are many that have stood out over the years. There are modern Seiko divers – like those from the Seiko Prospex line, modern Grand Seiko divers – like the SBGA463, and popular vintage Seiko divers – like the Seiko ‘Turtle’ 6306-7001. Among Seiko’s modern dive collection, there’s one Seiko diver that is quite popular among Seiko enthusiasts, but not so well-known outside of the Seiko community: the Seiko Marinemaster.

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The Seiko Marinemaster 300 SBDX001

Seiko Marinemaster 300 SBDX001 / Credit: Strapcode

While the history of Seiko’s professional dive watches goes back to the Seiko 6217-8000/1 ‘62MAS’ diver and the subsequent Seiko 6215-7000 diver, the Seiko Marinemaster is a much more modern invention. The first Seiko Marinemaster 300 SBDX001 hit the shelves in 2000 and was originally made exclusively for the Japanese market. While it is now over 20 years old, it remains an essential tool watch for divers – powered by Seiko’s automatic Cal. 8L35. Part of what makes it such a great dive watch is not only its movement, however, but also its design. While the Seiko Marinemaster 300 SBDX001 largely follows its predecessors in terms of shape and aesthetics, it does have a massive monobloc case that comes in at nearly 16 mm thick and 44 mm in diameter! It also has its crown at 4 o’clock, following in the tradition of the Seiko 5, and a depth rating of 300 meters. Pretty sold for any dive watch.

The First Seiko Marinemaster, the Marinemaster Quartz SBCN005

Seiko Marinemaster Quartz SBCN005 / Credit: Watchuseek user BJ19

Although the SBDX001 is the first automatic Marinemaster, there was actually a quartz model produced in the late 1990s before it, the Seiko Marinemaster Quartz SBCN005, with a titanium case. It also measured 44 mm in diameter and was powered by the Cal. 7K32 – a Seiko quartz movement. The Seiko Marinemaster Quartz SBCN005 is characterized by its blue dial with yellow hands that give it a distinctly aquatic feel. It seems that after trying to go the quartz route with their heavy-duty diver, Seiko instead switched over to trying with a mechanical watch, with which it was far more successful.

Other Seiko Marinemaster Models

A number of other Seiko divers are part of the Marinemaster line, to name a few, there’s the SBDX003, SBDX023, and the SBDC061, often called the ‘Baby Marinemaster’.

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Seiko Marinemaster SBDX003

The Seiko Marinemaster SBDX003 was released in 2000 just like the SBDX001. In reality it looks just like a Seiko 6159-7000 re-issue, with its gold markers, except it was made over a decade before the newer Seiko Limited Edition Prospex Hi-Beat SLA025. Being a limited edition of 500 pieces, the Seiko Marinemaster SBDX003 goes for quite a pretty penny these days. And like its counterpart the Seiko SBDX001, it is powered by the Seiko automatic Cal. 8L35 and also measures 44 mm in diameter.

Seiko Prospex Marinemaster SBDX023

A more modern iteration of the Seiko Marinemaster SBDX001, the Seiko Marinemaster SBDX023 shares many characteristics with the original. It is automatic with 26 jewels – still powered by the same Seiko Cal. 8L35 that also powered the original Seiko Marinemaster SBDX001, measures 44 mm in diameter, has a similar dial configuration, but instead of “MARINEMASTER” on the dial it has the Prospex logo. Still a heavy-duty tool watch, and a great dive watch.

Seiko ‘Baby Marinemaster’ SBDC061

Why is the Seiko SBDC061 called the ‘Baby Marinemaster’? The Seiko SBDC061 still measures 44 mm as part of the Prospex line like many other Marinemasters, but it only has 200 meters of water resistance, unlike the others that have 300 meters. It is also only about 13 mm thick, meaning it goes better with slimmer wrists and is a bit more compact than many of the other Marinemasters around. One con about this Seiko ‘Baby Marinemaster’ SBDC061, is that the bezel is noticeably thinner than with other, bulkier Seiko Marinemasters’, meaning that the dial is a lot more spacious, emptier even. A little detail, but it does make this one of my least favourite Marinemasters when it comes to looks. The Baby Marinemaster struggles somewhat to evoke the tool watch aesthetic that I really like about other Seiko Marinemasters, and that collectors really like about the original Seiko Marinemaster SBDX001.

By: Andres Ibarguen

Read more:

“Deep Dive: The Evolution of Seiko’s Professional Marinemaster Range.” Worn and Wound, February 26th, 2020, https://wornandwound.com/deep-dive-the-evolution-of-seikos-professional-marinemaster-range/.
“Seiko Marinemaster: How to Identify this Iconic Dive Watch?” The Watch Company, November 23rd, 2020, https://www.thewatchcompany.com/blog/seiko-marinemaster-how-to-identify-this-iconic-dive-watch/.