A Maritime Safety and Security Team, or MSST, is a counter-terrorism team of the United States Coast Guard established to protect local maritime assets. It is also a harbor and inshore patrol and security team that includes detecting and, if necessary, stopping or arresting submerged divers, using the Underwater Port Security System. It is the only special force that can arrest submerged divers.
MSSTs were created under the Maritime Transportation Security Act of 2002 (MTSA) in direct response to the terrorist attacks on September 11, 2001, and they are a part of the United States Department of Homeland Security's layered strategy directed at protecting seaports and waterways. MSSTs provide waterborne and a modest level of shore-side counter-terrorism force protection for strategic shipping, high interest vessels, and critical infrastructure. MSSTs are a quick response force capable of rapid nationwide deployment via air, ground or sea transportation in response to changing threat conditions and evolving Maritime Homeland Security (MHS) mission requirements. Multi-mission capability facilitates augmentation for other selected Coast Guard missions.
MSST personnel receive training in Advanced Tactical Boat Operations and counter-terrorism force protection at the Special Missions Training Center at Camp Lejeune, North Carolina.
The MSSTs operate as part of the Coast Guard's Deployable Specialized Forces, they are under operational control of the Coast Guard's corresponding Pacific and Atlantic Area commands, as well as an active reserve component of the White House on request.