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​Everything You Need to Know About the Rolex Sea-Dweller Series

27th Nov 2020

Rolex Sea-Dweller 126600

Rolex Sea-Dweller 126600

Designed for adventurers and oceanic explorers, the Rolex Sea-Dweller has gained a reputation as the finest deepwater timepiece in the world. Coveted by horologists across the globe, this stunning chronometer is a feat of engineering and innovation and deserving of a place in any watch enthusiast’s collection. If you are an avid diver or a lover of fine luxury watches, here is everything you need to know about the Rolex Sea-Dweller series.

A Brief History

The Rolex Sea-Dweller 126600 is a watch with a storied narrative spanning over 50 years and is inextricably linked with the history of diving. The original versions of the Sea-Dweller were based on the initial Submariner design, which was created following the dramatic increase in recreational diving after the end of WW2.

The Submariner was built to withstand aquatic environments up to 330 ft., which was later expanded to 660 ft. But to meet the needs of professional divers, Rolex collaborated with Comex, a French deep-sea diving company, to experiment with watches designed for saturation diving. From this research came the Sea-Dweller’s hallmark feature, the helium escape hatch, which allowed the watch to be worn in under-sea pressures up to three times that of the Submariner.

While the Sea-Dweller may not be as well known as the Submariner series, it has a heritage founded more on practicality rather than big-screen fame. Its high-pressure survivability makes it the go-to choice for divers spending a lengthy period at the ocean’s depths.

The Sea-Dweller’s History

Originally developed in 1967 for the diving industry, the Sea-Dweller came with a date dial on the right quarter for divers to better gauge longer stays underwater and was rated for up to 1,600 ft. submergence. The Double Red Sea-Dweller, produced between 1971 and 1977, featured a reference to the original Submariner on the face to make the Sea-Dweller more appealing to the public, who knew the Submariner from the James Bond movies. However, the Sea-Dweller transformed from the Double Red to the 1665, nicknamed the “Great White,” and it took on its own identity.

While the 1665 was still in production, further improvements were made, including a sapphire crystal and a larger helium escape valve, which meant an improved submergence rating for the watch up to a depth of 4,000 ft. This new edition was known as the 16660 model but was discontinued in 2008 and replaced by the Deepsea Sea-Dweller. A special edition Sea-Dweller, nicknamed the Deepsea Challenge, accompanied James Cameron to the bottom of the Mariana Trench, surviving a depth of 35,788 ft.

Rolex Sea-Dweller at Baselworld watch exhibition

Source: mmuenzl /

Helium Escape Valve

The Sea-Dweller was the first diving watch to be fitted with a helium release valve. Around the same time that the watch was being developed, archeological diver T. Walker Lloyd suggested using a one-way valve to resolve decompression issues.

The issue with underwater mechanisms is that saturation habitats contain an atmosphere with higher concentrations of helium or hydrogen. As the smallest natural gas particles, these gases can diffuse through various seals which block out water. As a diver decompresses, these gases expand and cause damage to the watch’s internal component, such as the crystal quite literally popping off due to the outward pressure.

As a solution, the helium escape valve automatically releases pressure when the force is enough to naturally overcome the tension of a spring. The spring activates the one-way valve, venting pressure within the watch and preventing damage.

Feature of the Rolex Sea-Dweller 126600

The Rolex Sea-Dweller 126600 has made many improvements over previous models, both aesthetically and mechanically. The 126600 has had its diameter increased to 43mm, with the rest of the watch being increased in size to maintain its stunning proportions. A cyclops lens was added over the date to ensure enhanced visibility.

Mechanically, the caliber 3135 internals have been upgraded to caliber 3235. This upgrade’s most significant improvement is an increased power reserve, from 48 hours up to 70 hours. This upgrade follows nearly 30 years of design using the caliber 3135. Based on how Rolex has been steadily upgrading all their new releases to caliber 3235, it is clear that they will replace caliber 3125 entirely in the future.

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Rolex Sea-Dweller wristwatch

Source: D-VISIONS /

In Conclusion

Whether it’s due to its rugged, practical looks, its thrilling history, or the prestige that comes from the Rolex brand, the Sea-Dweller holds something for everyone, especially for people who spend more time below sea level than above it. If you’d like to discover our entire luxury watch selection, including the Sea-Dweller and other Rolex watches for men and women, explore our online catalog.