The Coast Guard’s ninjas
While the Navy has the SEAL platoons that regularly deploy, and each ship frigate size and above has a multi-section VBSS team (blue jackets that have passed SRF-B and get three additional weeks training on insertion, collecting biometrics and team tactics), the Coast Guard also has similar programs.
Roughly the Coast Guard’s version of a VBSS team is a Law Enforcement Detachment (LEDET) while the nearest thing to a special operations unit is the Maritime Safety and Security Team or MSST and its counter-terror snake-eater unit, the MSRT.
Some 12 MSSTs (numbered 91101-91114) are spread around the country, co-located near high-value U.S. Navy bases (think Kitsap, Norfolk, Pearl, Kings Bay, et al) and ports. Composed of 75~ members, all they do all day is train for taking down high-risk maritime targets inside U.S.-controlled waters and hone such rare skill sets as underwater port security, and non-compliant vessel boardings. They also deploy abroad (CENTCOM, Guantanamo Bay, etc as needed). Further, all of the USCG’s canine teams are assigned to MSSTs.
They get very little press, but a lot of good training and equipment. If things ever get hot, they would be the ones looking for enemy frogmen, hijacked LNG tankers, CBRNE threats and USS Cole-style small boat attacks.

A member of U.S. Coast Guard Maritime Safety and Security Team 91101 Seattle stands watch in a ladderwell while his fellow boarding team members complete a sweep of Royal Canadian navy Kingston-class coastal defense vessel Yellowknife during a Trident Fury exercise in the Strait of Juan de Fuca, May 12, 2015. In order to complete their mission, the MSST team had to search every compartment on the vessel, subdue any potential aggressors and find a fake bomb that had been planted by a training team leader. (U.S. Coast Guard photo by Petty Officer 3rd Class Katelyn Shearer)

Members of U.S Coast Guard Maritime Safety and Security Team 91101 Seattle handcuff Ensign Jacob Sibilski, a crew member of U.S. Coast Guard Cutter Active, a 210-foot medium endurance cutter homeported in Port Angeles, Wash., while conducting a boarding of Royal Canadian navy Kingston-class coastal defense vessel Yellowknife as part of a Trident Fury exercise in the Strait of Juan de Fuca, May 12, 2015. Sibilski was acting as the captain of a Russian fishing vessel that had experienced a mutiny aboard. (U.S. Coast Guard photo by Petty Officer 3rd Class Katelyn Shearer) Click for hi rez
You have to love the Close Quarter Battle Receiver (CQBR) upper on the Mk18 rifles. We are talking 10-inch barrels here. Also note the FX Simunition marking cartridges in the clear mags (to ensure safety), blue “cold” markings and solid plastic Ring’s bluegun sidearms. Nothing like keeping it safe.