U.S. Special Forces wants to make its combat divers harder to detect

Somewhere underwater, a Navy SEAL is holding his breath, swimming toward an enemy ship in total darkness, counting on one thing to keep him alive: the fact that nobody on that ship can see him coming. The U.S. military wants to make absolutely certain that advantage never disappears, and it just asked American industry to help.

U.S. Special Operations Command published a solicitation on May 29, seeking companies that can deliver next-generation technology for combat divers, the special operations swimmers who infiltrate enemy harbors, attach explosives to warships, scout invasion beaches, and insert assault teams into places no helicopter or surface vessel could reach without being detected. The call covers six capability areas: better underwater propulsion, more advanced navigation, covert communications, life support systems, environmental protection, and signature management, which is the military’s term for making divers harder to detect. Proposals are accepted through June 2, 2026.

The document reads like a threat assessment as much as a procurement notice. “Our adversaries are rapidly developing advanced sensor networks and anti-access/area denial capabilities designed to detect and defeat maritime infiltration in contested environments,” it states. That sentence is about China, Russia, and Iran, all of which have invested heavily in underwater surveillance systems designed to find and track divers, submarines, and unmanned vehicles operating in their territorial waters. The underwater domain that special operations forces have relied on as a sanctuary for decades is becoming a contested battlespace, and the men swimming through it are carrying equipment that was designed before those detection systems existed.

The technology that makes a combat diver nearly invisible is the closed-circuit rebreather, a breathing device that recirculates the diver’s exhaled gas rather than releasing it. Standard scuba equipment produces a constant stream of bubbles rising to the surface, visible from above, audible on acoustic sensors below, and a reliable indicator of exactly where a diver is and where he is heading. A rebreather produces nothing. No bubbles, almost no sound, no surface signature. The diver simply disappears. The solicitation asks for next-generation rebreathers that extend how long a diver can stay submerged while meeting the qualification standards that life-support equipment for someone swimming in enemy waters in the dark absolutely has to meet.

Communications underwater presents a different kind of challenge. Radio waves that travel easily through air barely penetrate seawater. Acoustic signals work but generate detectable sound. Optical communications using blue-green laser light can push data through water at short ranges but require direct line of sight. USSOCOM wants companies with experience in both acoustic and optical underwater communications who can demonstrate how those systems integrate onto the underwater vehicles that deliver and support combat diver teams. The implicit requirement is obvious: divers need to talk to each other and to their support platforms without announcing their presence to every hydrophone in the area.

The propulsion technology named in the solicitation gives a sense of how far combat diver equipment has evolved from the fins-and-wetsuit baseline. Patriot3 Marine’s Jetboots, motorized thrusters strapped to a diver’s thighs, entered Navy SEAL service as early as 2020 and can push a swimmer at roughly four additional knots over a range of approximately 20 kilometers (12 miles) on a single battery charge. A $10 million contract in 2025 maintained and expanded the Jetboots supply chain. The CSO003 solicitation signals that endurance, noise, and integration with underwater navigation systems remain active gaps even with that capability already in the field.

Signature management is where the solicitation gets into territory that reads like science fiction but reflects a very real operational problem. A diver wearing a heating system to survive cold water generates a thermal signature. An underwater vehicle’s motor generates acoustic and electromagnetic emissions. Each of those signatures is a potential detection vector for adversary sensor networks that are becoming more sensitive and more comprehensive every year. The solicitation asks for companies with experience modifying propeller designs, thruster configurations, and sound-dampening approaches to push diver emissions below the detection threshold of systems that were specifically designed to find them.

The environmental protection requirements capture the geographic breadth of where USSOCOM actually sends its combat divers. The solicitation covers active thermal heating for cold-water operations, active cooling for warm-water missions in the Persian Gulf and South China Sea, protection against contaminated water exposure, and protection against dangerous marine life. Those categories span operations from the Norwegian coast in winter to the shallow tropical waters where sea snakes, stingrays, and aggressive sharks pose genuine risks to divers spending hours underwater without surfacing.

The Italians invented combat diving in 1941 when their frogmen rode manned torpedoes into Alexandria harbor and sank three British warships. The British copied the technique, then the Americans. For eight decades, the core tactical advantage of combat diving has remained constant: a man underwater is essentially invisible to the defenses that protect surface targets. China’s investment in undersea sensor networks around Taiwan and the South China Sea, Russia’s acoustic surveillance infrastructure in the Baltic and Arctic, and Iran’s Chinese-supplied detection systems in the Persian Gulf are all direct challenges to that assumption. USSOCOM’s solicitation is the acknowledgment that the assumption needs defending, and the technology that protects it needs to move faster than the sensors designed to defeat it.