Navy tests deep diving suit that doesn’t require decompression

The Navy is testing a prototype diving suit designed to protect deep-sea divers from crushing pressure and decompression sickness while reducing the suit’s weight, increasing visibility and mobility, and allowing divers longer periods underwater than older systems.

“It allows divers to descend without restrictions and not worry about bottom time and air limitations,” said Petty Officer 1st Class Onofre Lopez, one of the first Navy divers to test the suit in open water. “Bottom time is at a premium when you’re on surface-supplied air.”

The Gen 0 Deep Sea Expeditionary with No Decompression (DSEND) suit maintains a sea-level atmosphere, even at extreme depths, according to a Navy news release.

It’s an advancement on the older Atmospheric Diving Suit (ADS) previously used by the Navy, which also keeps divers at sea-level atmosphere, but is heavy, cumbersome, lacks mobility and requires a large support group for each diver.

According to the Navy and commercial diving catalogs, currently used diving suits can weigh more than 1,000 pounds with the lightest weight about 800 pounds. They require outfitting the diver, then using a winch from a boat or on shore to lower the diver into the water.

The new DSEND is considered a “lightweight” deep diving suit, according to the Office of Naval Research. But the DSEND still weighs in at under 500 pounds. While the diver must still be winched into the water, the relative lighter weight allow the diver to swim and move more easily using buoyancy devices when working at or near the seabed.

Prior to the tests in Keyport, DSEND was tested by the Navy at the University of Maryland in College Park. (Michael Walls/Office of Naval Research)

The Navy took the DSEND Gen 0 prototype to its top underwater warfare center, Naval Base Kitsap-Keyport, Wash., for evaluation last month. After tests in a pool at the University of Maryland, the suit was subjected to the open-water environment of Puget Sound, west of Seattle.

Sponsored by the Office of Naval Research in partnership with Naval Sea Systems Command, the evaluation moved the suit from a controlled facility into a realistic, unpredictable saltwater environment.

Three Navy divers piloted the prototype to the ocean floor to simulate real-world missions such as underwater rescues, salvage, explosive ordnance disposal and hull maintenance.

The tests at Keyport included recovering an unmanned underwater vehicle that the Navy sank for the exercise. The divers, working in tandem with remotely operated “topside” engineers, successfully located the UUV, rigged a lifting device using the suit’s mechanical grippers and secured the vehicle for recovery.

“The rigorous testing exposed the suit to factors like variable visibility, limited traction and a silty/muddy seafloor, allowing the divers to assess its maneuverability,” the Navy release said.

Divers using standard scuba gear can usually operate down to about 130 feet below the ocean’s surface. The DSEND suit allows divers to work in pressure equal to sea level at depth down to 600 feet.

Navy Diver 2nd Class Giovanni Casteñeda is lowered into Liberty Bay near Seattle while wearing a Deep Sea Expeditionary with No Decompression (DSEND) suit. The test at Naval Undersea Warfare Center Division, Keyport, Wash., on June 9, 2026. (Scott Pittman/U.S. Navy)

Older deep-sea Navy diving suits use a mixture of oxygen and inert gases such as helium and nitrogen, so divers can work several hundred feet below the surface.

But deep underwater work can increase nitrogen narcosis — known as “rapture of the deep” — in which the pressurized nitrogen can cause altered states of consciousness similar to alcohol intoxication. Divers must also lower and raise themselves back to the surface, using frequent stops to fend off decompression sickness, known as “the bends.”

Divers sometimes must be put inside decompression chambers after surfacing in order to smooth their adaption to sea-level air pressure.

“The overall goal of the program is to be able to do one-atmospheric diving, to reduce and eliminate the risk of decompression sickness, and reduce the effects of bottom time on the diver,” Navy Chief Warrant Officer 2 Chris Lansford said.

The lightweight atmospheric suit, which has been in development since 2017, looks more like one worn for missions in outer space than the traditional heavy-metal deep-sea diving outfit. It has rotating joints that allow for better mobility than older suits and is fitted with a self-contained life support system.

To ensure divers can perform complex tasks, the team evaluated mechanical gripper dexterity, rotational-joint durability in high-particulate environments and fine motor skills. Divers successfully adapted hand pods for underwater tool usage, demonstrating the physical versatility required for salvage operations.

Divers can use a prototype thruster pack that enhances speed and buoyancy to counter the suction of heavy boots on muddy seafloor terrain.

Lopez said the suit’s buoyancy created minor challenges but was just a “little bit of a growing pain” for divers getting used to balancing it.

“But other than that, It allows us to stay comfortable essentially indefinitely,” he said.

The Navy said data gathered from the tests will be used to update the design and performance of the planned Gen 1 prototype for DSEND.

Navy Diver 2nd Class Giovanni Casteñeda prepares to enter a Deep Sea Expeditionary with No Decompression (DSEND) suit during an exercise at Naval Undersea Warfare Center Division, Keyport, Wash., on June 9, 2026.   (Scott Pittman/U.S. Navy)