Seiko Unveils Three Prospex Timepieces Dedicated To The Most Challenging American Diving Locales

by Sameera Gamage

Seiko releases three new timepieces that are U.S Special Editions only, inspired by some of the most demanding American cold-water diving locations. 

As some may know, 1965 was the year the first Seiko diver’s watch (62MAS), in fact Japan’s first diver’s watch was released. The Seiko 62MAS was capable of guaranteeing a water resistance of up to 150 meters deep. The watch has quite a history, not only has the first diver’s piece, but also because it was the first diver’s watch that was provided as professional equipment for the researchers of the Japanese Antarctic Research Expedition (JARE).

Now, somewhat almost 60 years later, the design of the modern Seiko diver’s watch still carries the same design and aesthetic characteristics of what made the 62MAS iconic. Since the creation of the 62MAS, Seiko diver’s watches have earned the trust of professional divers and diving enthusiasts over time, thanks to improvements and innovations in durability, water resistance, and precision. 

Seiko Prospex U.S. Special Edition Ref SPB421 (left), Ref SPB419 (middle) and Ref SPB423 (right).

This latest collection of timepieces is continuing Seiko’s spirit of exploration with the classic mid century design, now being inspired by the most challenging diving locations in America. Each watch carries the same movement underneath, with only the dial colour aesthetics being changed between the three timepieces. The colours reflect the conditions of each location chosen to be represented by that watch. The three models have a very generous amount of SuperLumi-Nova coatings on the hour indices and hands, all of which will help with dial readability in those low-light diving conditions.

Seiko Prospex U.S. Special Edition Ref SPB423 Close Up Dial View.

All three dials come with an intricate 3 -dimensional pressed pattern , which Seiko states “vividly recalls the colours one might encounter exploring some of the world’s most challenging diving environments.” Each dial has it’s own characteristics thanks to the colours, which is also reflected on the bezel to match the dial nicely. Personally out of the three choices available, the ice blue (ref SPB419) stands out beautifully as its a reflection of the Michigan blue ice. Unlike the other two models, the gradient colour effect on this model is easily noticeable, as it goes from the ice blue colour in the centre to a darker tone on the edge of the dial.

Beautiful Icy Blue Dial Of The Seiko Prospex U.S. Special Edition Ref SPB419.

All three models are presented on Seiko’s easily recognizable classic case design, which sits at 40.5mm diameter, and one that Seiko states “will transport the wearer back in time to the birth of the legendary first Seiko diver’s watch”. It is quite true as the 62MAS bared the exact same case design, however, this modern variation has a more refined and streamlined case, to give the wearer a much more comfortable fit on the wrist.

Seiko Prospex U.S. Special Edition Ref SPB421 Close Up Dial View.

Seiko is powering these timepieces with their modern Calibre 6R35 self-winding 24-jewel mechanical movement. The Calibre 6R35 movement operates at a frequency of 21,600 VpH and gives out an impressive power reserve of approximately 70 hours. The watch is also rated to a depth of 200 meters and has been engineered for compliance with the relevant ISO standards and specifications for diving. Each model is presented in Seiko’s classic 3-link bracelet design.

As the aesthetics of these three new models inspired by America’s challenging diving locations makes it’s way into the Prospex line-up, it’s easy to see some of these models will be an instant hit, even as a daily go-to-watch thanks to the sturdiness, movement and beautiful aesthetics of the timepieces. These 2023 Prospex U.S. Special Editions are launched exclusively in the United States and is available at select Seiko retailers from September 2023.

Let’s take a look at the in more detail…

Seiko Prospex U.S. Special Edition Ref SPB419

The Ref SPB419 comes with an icy-blue gradation dial and has been inspired by the Michigan blue ice. The Michigan blue ice is a rare phenomenon that occurs along the coastline of the northern Great Lakes.
This rare phenomenon occurs when the ice forms slowly and evenly, taking the shape of large crystals which allow the light to penetrate deeply, which ultimately causes the frozen water to take vivid blue colour.

Seiko Prospex U.S. Special Edition Ref SPB421

The Ref SPB421 takes it’s inspiration from Alaska and the state’s remote glacial moulins. The breath-taking phenomenon that is the Alaska moulin, is formed when the meltstream penetrates the surface of a glacier, and go all the way down to the bottom of a glacier, which can be hundreds of meters deep!

The Ref SPB421 dial has a dark blue hue with a subtle gradation, evoking the colours viewed at the depths of the moulin.

Seiko Prospex U.S. Special Edition Ref SPB423

The Ref SPB423 takes the same design and dial inspiration as previous Ref SPB421. Inspired by the Alaska moulin’s, this timepieces dial highlights the light gray tones of glacial ice with its gradated dial. 
Besides the icy blue dial of Ref SPB419, this timepiece’s gradient colour effect is easily visible as well, and offers a more subtle appearance compared to it’s companions.

Reference: SPB419, SPB421, SPB423


  • Case: 40.5 mm, thickness: 13.2mm
  • Case Material: Stainless steel case with super-hard coating.
  • Case back: Screw-down crown, screw case back.
  • Dial: Gradient icy blue dial (Ref SPB419), dark blue dial (Ref SPB421) or light grey dial (Ref SPB423).
  • Crystal: Curved sapphire crystal with anti-reflective coating on the inner surface.
  • Water resistance: 200m / 20 bar
  • Movement: Automatic Caliber 6R35
  • Power reserve: Approximately 70 hours
  • Strap:  Three-link stainless steel bracelet with super-hard coating

International Recommended Retail Price: USD $1,250

Availability: Launched exclusively in the United States and is available at select Seiko retailers from September 2023.

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