Seiko Watches and Their Role in the History of Dive Timepieces

When it comes to the evolution of dive watches, Seiko holds a special place in the horological hall of fame. While many brands have contributed to the development of diving watches, Seiko’s approach—practical, innovative, and often ahead of its time—helped shape the category into what it is today. From creating robust tools for professionals to making dive watches accessible to everyday enthusiasts, Seiko’s legacy under the waves is both deep and influential.

The Birth of a Legend: Seiko’s First Dive Watch

Seiko’s journey into the world of dive watches began in 1965 with the release of the 62MAS (ref. 6217-8000)—Japan’s first-ever diver’s watch. It featured 150 meters of water resistance, a screw-down crown, a rotating bezel, and strong legibility—key attributes for any serious dive watch. While Swiss brands had already entered the diving world, the 62MAS marked a turning point for the Japanese watch industry and laid the foundation for Seiko’s dive watch legacy.

The 62MAS wasn’t just a design exercise. It was tested and used in real-world expeditions, including by members of the Japanese Antarctic Research Expedition, proving its durability in extreme conditions.

Raising the Bar: The 1968 300m Professional Diver

In 1968, Seiko released the ref. 6159-7001, a professional-grade dive watch with 300 meters of water resistance and a high-beat automatic movement (36,000 vibrations per hour). This model brought mechanical performance and precision to a level rarely seen in diving watches at the time. Its monobloc case construction increased durability and reduced the risk of water ingress—an innovation that reflected Seiko’s practical, problem-solving ethos.

The Birth of the Tuna Can: Purpose-Driven Design

Perhaps one of the most iconic dive watches Seiko ever created is the Seiko “Tuna”—a nickname given to the 1975 Professional Diver's 600m (ref. 6159-7010) due to its chunky, cylindrical case. This wasn’t just a stylistic choice. The Tuna was born out of a letter Seiko Diamond Watch received from a professional diver who reported issues with traditional dive watches failing at great depths.

Seiko responded by developing a titanium monocoque case, L-shaped gaskets, and a unique shroud to protect the bezel and crystal. It was also the first dive watch with a titanium case, and the first to use quartz technology in saturation diving conditions. The result? A watch that didn’t just meet ISO standards—it often exceeded them.

This no-nonsense, form-follows-function approach made the Tuna beloved by commercial divers and collectors alike. The design remains virtually unchanged decades later, a testament to how well it was executed.

ISO Standards and Industry Influence

Seiko has been instrumental in shaping international standards for dive watches. In fact, Seiko’s rigorous internal testing and design philosophies helped influence the ISO 6425 standard—the globally accepted benchmark for what qualifies as a dive watch.

Features like unidirectional bezels, luminous markers, minimum water resistance, and shock resistance were all part of Seiko’s DNA before ISO formalized them. The brand’s commitment to creating watches that perform reliably under pressure helped raise the industry standard for what a true dive watch should be.

Making Dive Watches Accessible

While Seiko excels at professional-grade dive watches, it’s perhaps even more famous for democratizing the category. Iconic models like the Seiko SKX007, Turtle, and Monster have become staples in the collections of both beginners and seasoned collectors. These watches offer legitimate dive functionality—200 meters of water resistance, screw-down crowns, ISO certification—at price points that are hard to beat.

This accessibility has made Seiko dive watches a “gateway” into the world of mechanical watches for many enthusiasts. The SKX line, in particular, became a cult classic, praised for its robustness, timeless style, and unbeatable value.

Modern Icons and Technological Evolution

Today, Seiko’s dive watch lineage continues through collections like Prospex (Professional Specifications), which blends the brand’s heritage with modern materials and movements. From solar-powered dive watches to automatic models with ceramic bezels and sapphire crystals, Seiko continues to evolve the dive watch formula without losing sight of what made it successful: reliability, clarity, and durability.

Recent reissues of the 62MAS, reinterpretations of the Turtle, and modern takes on the Tuna show that Seiko understands the value of its history. These models cater to both purists who value vintage aesthetics and modern users who demand cutting-edge performance.

Conclusion: A Lasting Legacy Beneath the Waves

Seiko’s contribution to the history of dive watches is not just about ticking boxes or following trends—it’s about leading with innovation and integrity. Whether it’s pioneering new materials, developing groundbreaking technology, or simply making excellent dive watches accessible to the masses, Seiko has played a vital role in shaping the modern dive watch landscape.

From the icy cold of Antarctica to the crushing depths of the ocean, Seiko dive watches have proven themselves time and again. Their reputation is well-earned, and their influence on both the industry and watch culture is undeniable.