A deep-submergence rescue vehicle (DSRV) is a type of deep-submergence vehicle used for rescue of downed submarines and clandestine missions. While DSRV is the term most often used by the United States Navy, other nations have different designations for their vehicles.
ASRV Remora ("Really Excellent Method Of Rescuing Aussies") was the Australian navy's DSRV. It is based on a diving bell design.
The People's Republic of China has three Type 925 Dajiang class and three Type 926 class. Each ship is equipped with either two Type 7103 DSRV or one LR7 crewed submersible undersea rescue vehicle.
France, Norway and the UK share the NATO Submarine Rescue System programme.
Italy operates Anteo, equipped with the SRV-300 submersible in a submarine rescue role 
The Swedish Navy operates the submarine rescue ship HSwMS Belos which can carry the Swedish submarine rescue vessel URF (Swedish: Ubåtsräddningsfarkost) as well as the British LR5.
Main article: LR5
The United Kingdom operates the LR5 submersible in a submarine rescue role built by Forum Energy Technologies's Subsea Division. It previously operated the LR3 built by Slingsby Engineering, which became part of Forum Energy Technologies (FET).
The Indian Navy inducted its first DSRV in November 2018 and second in 2019.
The Japan Maritime Self-Defense Force operate two DSRVs with dedicated mother ships.
The Korean navy operates a submarine rescue ship called Cheong Haejin. It has a dedicated mother ship. The model is based on a modified British design.
Russia is believed to have one vessel of the Bester class and four of the Priz class, which was involved in the failed attempt to rescue the crew of Kursk.
MV Swift Rescue, launched 29 November 2008, is Singapore's first and only submarine recovery vessel. It is equipped with a deep submergence rescue vehicle.
The vessel consisted of a Submarine Support and Rescue Vessel (SSRV) SSRV mother vessel proper and an integrated Submarine Rescue Vehicle (SRV), built by ST Marine at its Benoi Shipbuilding Yard in Singapore with its UK joint venture partner JFD based on its proprietary Deep Search and Rescue (DSAR) 500 Class submarine rescue vehicle platform, It also has an underwater drone ROV and a helipad.
The Republic Of Singapore Navy has signed submarine rescue agreement with Australia, Indonesia, Malaysia, Vietnam, and United States to assist in submarine rescue efforts for their respective submarine fleets.
The mode of deployment for these United States submersibles is: fly the vehicle to the port closest to the incident; attach the vehicle to a host submarine; the host submarine travels to the incident site; rescue. The DSRVs were originally designed to work with USS Pigeon and USS Ortolan, but those two vessels have since been decommissioned and replaced by the Submarine Rescue Diving Recompression System.
The Deep Submergence Rescue Vehicle (DSRV) is designed to rescue 24 people at a time at depths of up to 600 m (1,969 ft). Their maximum operating depth is 1,500 m (4,921 ft). Power is provided by two large batteries, one fore, and one aft that power the electrical, hydraulic and life support systems. The DSRV uses mercury in a completely sealed system to allow themselves to match any angle (up to 45°) in both pitch and roll so as to "mate" (attach) to a downed submarine that may be at an angle on the sea floor. The DSRV is capable of being transported by Air Force C-5 to anywhere in the world within 24 hours.
It is then loaded onto a "Mother Submarine" (MOSUB). The MOSUB then carries the DSRV to the rescue site where several trips are made to rescue all personnel. Rescue is usually accomplished by ferrying rescuees from the stranded sub to the MOSUB, however, they can also be taken to a properly equipped surface support ship.
In addition to a number of U.S. Navy submarines being outfitted for MOSUB capabilities, several NATO countries also have submarines outfitted to carry the U.S. Navy DSRV for rescue capability as needed. Both the UK and French Navies have such submarines.
The interior of the DSRV is composed of three spheres. The forward sphere is the "Control Sphere" where the DSRV's pilot and copilot operate the vehicle. The two aft spheres (known as Mid Sphere and Aft Sphere) are used to seat the rescuees or to install equipment for additional operations. Maneuvering is accomplished using four thrusters and one main propeller.