The quest for the world’s most waterproof timepiece has been going on at, at this point, for the better part of a century — and in a sense you could say it’s been a decades-long battle of record-setting between a handful of bold and technically ambitious watch manufacturers. If we want to stick with that analogy, the latest salvo was fired earlier this year by Omega, which — somewhat quietly, until its big reveal on June 20 at London’s British Museum — built a special model of the Seamaster Planet Ocean that accompanied adventurer and explorer Victor Vescovo in his record-breaking descent into the Mariana Trench, the deepest point in all of Earth’s oceans, and thus established a new standard for wristwatch water-resistance.

The case is made from Grade 5 Titanium

Vescovo, as part of his “Five Deeps” series of expeditions to the deepest points in all of Earth’s five oceans, piloted the Limiting Factor, a specially built submersible whose hull is made of grade 5 titanium, into the Challenger Deep, the deepest part of the Marian Trench. (You may recall that Rolex, famously reached a then-record depth of 35,787 feet in the Challenger Deep back in 2012, in an expedition headed by filmmaker James Cameron. Vescovo’s expedition discovered a slightly deeper point, reaching 10,928 meters, or 35,853 feet.)

The case has a massive 28 mm profile

The 55-mm case of the Seamaster Planet Ocean Ultra-Deep Professional — only three were made, and none for commercial sale — was machined from cutouts from that titanium hull and required the use of a new, weld-free forging technique. The impressive result was a case that measured just shy of 28 mm thick but was tested to withstand water-pressures to an astounding and unprecedented 15,000 meters — basically 22.5 tons of pressure.

Obviously it’s not just the case itself that is a concern in a watch for extreme depths, but the sapphire crystal. Omega took inspiration from the loadbearing conical design of the viewports on the Limiting Factor submersible, using LiquidMetal, a material Omega and other brands within the Swatch Group have long utilized, for a “firm yet flexible” assembly.

Hot bonding technique was used to reduce the thickness of the crystal

Omega’s patent-pending “hot bonding” technique allowed the watchmakers to avoid the use of more traditional polymer seals and thus reduce the crystal’s thickness. The openworked “Manta” style lugs are fully integrated into the case and help reduce the case’s overall load. The Five Deeps Expedition logo is engraved on the caseback in a pattern of concentric circles that evoke the sonar technology used in the expeditions.

The manta-ray inspired lugs construction

Despite its massive size and high-tech tooling, the watch is in every sense an Omega, and the company has already stated that some of its technical innovations will be applied to future commercial dive watches. It has a matte black dial (thus to avoid reflections underwater) with luminous numerals, a ceramic dive-scale bezel, a sandblasted finish on the titanium case, and even an element that alludes to Omega’s Moonwatches from the Speedmaster family: a polyamide strap with a velcro closure, similar to the type used on space missions.

The straps were chosen strategically as the best type to fasten and hold the three Ultra-Deep in their positions outside the hull of the submersible — two attached to the robotic arms, the other to one of the “landers” that scour the ocean floor for scientific data.

For Omega, the Seamaster Planet Ocean Ultra-Deep Professional is not just about World’s Deepest Watch bragging rights but a new chapter in its diving history — from the Omega Marine in 1932 to the first Seamaster in 1948, to the game-changing Seamsaster 300 in ’57 and Ploprof in ’70, and beyond. It just goes to show that even in an Omega year so dominated by its history of space travel, the brand is still making historic strides right here on Earth.