📅 Monday, August 24, 2026
Long before the Deepsea Challenge went to the Mariana Trench, Rolex attached an experimental ‘Deep Sea Special’ watch to the outside of the Trieste bathyscaphe in 1960. The massive bubble-domed timepiece withstood a crushing pressure of over seven miles down in the Challenger Deep and continued ticking normally. When the hatch opened, the watch proved that mechanical engineering could conquer the most extreme depths on Earth.
On January 23, 1960, Swiss oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh climbed aboard the experimental bathyscaphe Trieste and began descending into the Mariana Trench. Their destination was Challenger Deep, the deepest known region of Earth’s oceans. Strapped not safely inside the pressure sphere, but deliberately to the outside of the vessel, was an experimental Rolex unlike anything intended for an ordinary wrist: the Deep Sea Special.
The watch was the culmination of years of experimentation. During the 1950s, Rolex had developed successive Deep Sea Special prototypes specifically to explore the limits of waterproof watch construction. For the extraordinary pressure anticipated at Challenger Deep, the watch used a remarkably thick, highly domed crystal, giving the prototype its unmistakable almost bubble-like appearance. Rolex says the third Deep Sea Special was created specifically to withstand the extreme conditions of the Mariana Trench.
Then the Trieste kept going down.
1,000 metres.
5,000 metres.
8,000 metres.
10,000 metres.
Eventually Piccard and Walsh reached a record 10,916 metres — 35,814 feet, or roughly 6.8 miles — beneath the Pacific Ocean. That’s deeper than Mount Everest is tall, with roughly another two kilometres to spare. At that depth, Rolex says the Deep Sea Special endured pressure exceeding one tonne per square centimetre.
And remember where the watch was.
There was no protective pressure cabin around it. While Piccard and Walsh survived inside the Trieste’s heavily reinforced pressure sphere, the Deep Sea Special was exposed directly to the abyssal environment on the exterior of the bathyscaphe. Its case and crystal therefore had to resist the crushing pressure of Challenger Deep while maintaining the sealed environment necessary for the mechanical movement inside.
After approximately eight and a half hours beneath the sea, the Trieste returned to the surface. The experimental watch was recovered—and Rolex reports that it had kept perfect time. The result was dramatic proof that a properly engineered mechanical wristwatch case could remain watertight under one of the most hostile pressure environments accessible on Earth.
Piccard then sent Rolex a telegram that became part of watchmaking folklore:
“Glad to report your watch as accurate at 11,000 metres as on land.”
That is Rolex’s documented wording of Piccard’s message following the dive.
The Story Didn’t End in 1960
For more than half a century, the Trieste achievement stood essentially alone. Then, on March 26, 2012, filmmaker and explorer James Cameron descended solo to Challenger Deep aboard the DEEPSEA CHALLENGER. Once again, an experimental Rolex was mounted outside the submersible—this time the enormous Rolex Deepsea Challenge, engineered for waterproofness to 12,000 metres. Rolex says it remained accurate at more than 10,000 metres and emerged unscathed.
And there’s a wonderful connection between the two expeditions: Cameron actually carried a 1960 Deep Sea Special inside his cockpit during the 2012 dive. He called the vintage watch the “Old Lady” and described it as his good-luck charm—a sister watch to the Deep Sea Special that had made the original journey aboard Trieste 52 years earlier.
That heritage eventually reached a production wristwatch. In 2022, Rolex introduced the titanium Deepsea Challenge, guaranteed waterproof to 11,000 metres (36,090 feet). Its caseback carries the dates 23-01-1960 and 26-03-2012, permanently connecting the production model to the Trieste and Cameron expeditions.
💡 Did You Know?
The famous Deep Sea Special wasn’t tucked into the Trieste’s cockpit as a souvenir—it was attached to the exterior specifically so that the ocean could attack it with essentially the same immense environmental pressure confronting the bathyscaphe itself. At Challenger Deep, Rolex records pressure of more than one tonne per square centimetre, yet when the watch returned to daylight, its mechanical movement was still keeping time
Category: Military Watches
Disclaimer: Every effort has been made to keep these watch facts accurate, but the world of horology is full of myths, disputed stories, and fascinating trivia. Consider these facts a starting point for discovery rather than the final word. If you have corrections or additional insights, let us know—we’re always happy to keep the record ticking in the right direction.
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