Seiko Story: Why Seiko Marinemaster 300m is Still the Top Choice Among Professional Divers

Seiko is renowned for creating exquisitely-crafted diving watches that fit everybody’s lifestyle, especially the adventurers, professionals, watch aficionados, sports enthusiasts, and everyone in between.

Japan has always been big and hard at work when it comes to creating timepieces that can endure the conditions of deep-sea diving. From Swiss watch-inspired designs to avant-garde creations, they never settle for less. 

An excellent movement marks the greatness of the Seiko Marinemaster. The goal of Seiko is to raise the art of watchmaking to its peak by relentlessly incorporating the latest technology and their intricate craftsmanship to ensure movement precision and mechanical accuracy at its finest, especially for diving needs.

History of Seiko Marinemaster

The heritage of the dive watch began in 1960 during the time when divers really needed an affordably priced but professionally adequate watch. 

The divers need to constantly monitor their dive time with a reliable timekeeping instrument. 

Seiko was the first ever to release a diving watch in Japan and this came to fruition through a diver’s fateful letter. He expounded how all their watches got damaged in depths greater than 300 meters while using a diving capsule. 


(Source: Monochrome)

Seiko 6159-7001 is the first Marinmaster, powered by Seiko 6159A calibre,  a hi-beat (36,000 bph) movement. 

This concern laid the groundwork and fueled Seiko to innovate and create more revolutionary watches that can withstand deep and hardcore underwater activities.

Up to date, the relentless pursuit of creating distinct timepieces with advanced horological technology for divers is Seiko’s mission.

With their passion and dedication to creating more state-of-the-art diver watches, Seiko introduced the Marinemaster series under their Prospex line. Another iconic timepiece series that absolutely keeps up with any diver’s professional needs and lifestyle.

(Source: ablogtowatch) The Seiko SBDX001 is the first modern Marinemaster and powered by the 8L35 calibre, a 28,800 bph movement. 


Undeniably, one of the most-loved dive watch series among professional divers is the Seiko Marinemaster. 

Marinemaster truly delivers and challenges every limit. The design is impeccable, stylish, classic, rugged, yet absolutely luxurious. The specifications are top-of-the-line with 300-meter water resistance.

It offers the finest mechanical automatic movement with up to 50 hours of power reserve.

The accuracy easily matches the level of a certified chronometer and often exceeds it.

Seiko Marinemaster’s monocoque is superb and the basic physics behind the case design had been proven over the course of a generation. This only proves that the production capabilities and techniques of Seiko grew and became even more advanced. 

For Seiko obsessives around the world, the Marinemaster series represents the pinnacle of timepiece engineering. Seiko has always been about function over form and this principle is beautifully magnified in each watch.

It is extremely comfortable to wear and the straps can also be replaced with Curved End Rubber Strap for Seiko MM300 (CB03).

The Seiko SBDX023 is the latest Marinemaster. Many enthusiasts are upset that the "Marinemaster" no longer exists on the dial. 


It is quite hard to pin down the cons of Seiko Marinemaster. But many collectors initially notice that the crown is unsigned which may be a bit of a let-down. Another small issue is the glossy bezel which looks wonderful in stainless steel with lacquer but can still be scratched of course. 

Other than these tiny issues, the Marinemaster 300m is a truly remarkable timepiece that is worth every penny and is still the best in class.


Model Numbers:

















Dial: LumiBrite markers

Case Material: Stainless steel

Case Dimensions: 44.2mm in diameter, 15.4mm in height, and 50mm lug-to-lug

Crystal: Sapphire

Movement: Calibre 8L35, self-winding movement, 28800vph

Power Reserve: 50 hours