Landlocked Switzerland may think it has cornered the market for tough and reliable dive watches, but the island nation of Japan was setting the pace back in 1965 when Seiko produced its 150 meter-resistant “62MAS”.

That watch set Seiko on a path of continuous improvement and innovation that continues to this day, and along the way its watches have been worn by some of the world’s greatest adventurers on extraordinary expeditions.

Rob Corder follows Seiko’s watchmaking journey that sees its dive watches conquering the highest peaks of Alaska and Asia, the frozen beauty of Antarctica and the deepest oceans of the Pacific Ocean.


Seiko’s dive watches are built for people who take on the greatest challenges in the harshest conditions on the planet and have been tested and trusted by some of the world’s legendary adventurers.

Few are more revered in Japan than Naomi Uemura, a legendary explorer who was the first man to reach the North Pole solo in 1978 and the first to climb Alaska’s Mount McKinley, now known as Denali, on his own in 1970.

Legendary Japanese adventurer Naomi Uemura conquered Mt Everest wearing a Seiko ref.6105 dive watch.


Before his 30th birthday, Mr Uemura had solo-climbed Mount Kilimanjaro, Aconcagua, Mont Blanc, and the Matterhorn, had walked the length of Japan.

In 1970, he became the first person from Japan to summit Mount Everest, and this adventure is celebrated 50 years on by Seiko because its ref.6105 professional diver’s watch from that year, now known to collectors as the Captain Willard (an Apocalypse Now reference), was a critical part of the climber’s equipment.

An anniversary watch to mark 50 years since that Everest adventure arrived earlier this year in the form of the Seiko Prospex SPB153, a Luxe collection model retailing at an attractive $1,100. The substantial 44m cushion shape-cased 1970 original has been trimmed down to a 42.7mm diameter model offered with black or olive green dials and color-matched unidirectional bezels.

Divers will appreciate the bold indexes and hands filled with glow-in-the-dark LumiBrite, 200 meter water resistance and the choice of stainless steel bracelet or a silicone strap.

This fall, Mr Uemura’s adventures in the frozen wilds of Alaska and Antarctica have inspired a range of Prospex Built for the Ice Diver watches. As with the original expedition and Mr Uemura’s original watch, this new collection continues Prospex’s legacy of building products for people who take on the greatest challenges.

There are three steel on steel models in the collection, the SPB175, 177 and 179 in gray, green, and blue colors inspired by the way light reflects off glacial ice.

Each version is water resistant to 200 meters, has a unidirectional bezel, sapphire glass and a screw-in crown. Inside, the automatic 6R35 movement has a power reserve of around 70 hours. As with their originals, PROSPEX which were built for the Ice Diver, are ISO certified, ensuring that the rigorous standards required of extreme adventures are maintained.

They are available exclusively in the United States from September for $900.

Seiko has never needed to dramatically redesign its original divers’ watch, the 1965 150m “62MAS”, because its timeless looks and professional specs make it as useful, reliable and wearable today as it was back then. Good condition originals now sell for over $5,000, despite being a little small for current tastes in their 37mm stainless steel cases.

Hunting for these rare heritage pieces is now a passion project for collectors, but the more casual watch enthusiast has an alternative this year in the form of Seiko’s Prospex SPB143, SPB145 and SPB147 special editions that bring the 62MAS up-to-date in models made from high grade steel 40.5mm cases and using double-domed anti-reflective sapphire crystal instead of the original plexiglass.

Seiko’s Prospex SPB145, SPB143, and SPB147 special editions bring the pioneering 62MAS up-to-date.

The movement is upgraded from the 6217A to Seiko’s modern 6R35 automatic, which has a 70 hour power reserve. At $1,000 to $1,200, this year’s re-interpretations. are among the most impressive dive watches available at such an attractive price point, and a crowning example of Seiko’s peerless expertise in affordable professional timekeepers over the past 55 years.

Seiko is using this 55th anniversary of the 62MAS to remember many of the other great divers’ watches it has made in subsequent years and the stories of great exploration and adventure associated with them including the exploits of Naomi Uemura.

As the earth’s highest peak, reaching the summit of Mount Everest is certainly one of the world’s greatest challenges, but its freezing temperature and altitude is not as tough on timekeepers as the deepest oceans, and this is a place for which Seiko’s 1975 saturation diver watch the Professional Diver 600m, nicknamed the Tuna because of its slightly bulbous underbelly, was designed.

Officially, the watch was credited with water resistance to 600 meters, but Seiko wanted to know how deep it could go so, in 1983, two of the watches were mounted on the outside of a research submersible used by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). The institute’s Shinkai 2000 sub descended to a depth of 1,062 meters while the watches’ remained unscathed.

Seiko’s Professional Diver 600m survived to a depth of 1062 meters attached to a Japan Agency for Marine-Earth Science submarine in 1975.

The Tuna is also back this year with a modern makeover in two new references: the 49.4mm S23631, which can operate at depths of up to 1000 meters and the slightly smaller 47.7mm S23629, which is classed as a 300 meter dive watch. The S23631 comes in a titanium and ceramic case while the S23629 is in stainless steel.

In this case, Seiko eschewed the automatic mechanical movement for the more accurate 7C46 caliber, a quartz movement designed specifically for Diver’s watches. They went on sale this summer for $2,400 and $1,450.

Seiko’s history and innovation in the field of professional and recreational divers’ watches is every bit as rich and accomplished as legendary Swiss watchmakers such as Rolex, Omega and Blancpain, and the Japanese watchmaker is recognized and respected in Switzerland for the quality of its modern timekeepers.

Seiko has won prizes for its watches at the Grand Prix d’Horlogerie de Genève (GPHG) on multiple occasions. Its Spring Drive Spacewalk Commemorative Edition was named the Sports Watch of the Year in 2010 and was praised for being the only watch in the world designed from scratch to be worn during a spacewalk.

In 2019, Seiko’s titanium Prospex LX, which also uses the Spring Drive movement, earned the gong in GPHG’s Diver’s Watch category and is now, arguably, Seiko’s signature watch. Spring Drive takes precision to a new level for mechanical watches, achieving +/- 1 second per day accuracy and delivering its power perfectly to a smoothly sweeping seconds hand.

Its unique architecture and engineering also make it highly resistant to temperature and pressure variations; vital qualities that show the constant improvements seen over Seiko’s 55 years’ of watchmaking for divers.

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