Modern U.S. frigates mainly perform anti-submarine warfare for carrier and expeditionary strike groups and provide armed escort for supply convoys and merchant shipping. They are designed to protect friendly ships against hostile submarines in low to medium threat environments, using torpedoes and LAMPS helicopters. Independently, frigates are able to conduct counterdrug missions and other maritime interception operations. As in the case of destroyers, frigates are named after U.S. Navy, Marine Corps, and Coast Guard heroes. As of autumn 2015, the U.S. Navy has retired its most recent class of frigates and expects that by 2020 the Littoral Combat Ships (LCS) will assume many of the duties the frigate had with the fleet.
The LCS is a class of relatively small surface vessels intended for operations in the littoral zone (close to shore). It was "envisioned to be a networked, agile, stealthy surface combatant capable of defeating anti-access and asymmetric threats in the littorals". They have the capabilities of a small assault transport, including a flight deck and hangar for housing two helicopters, a stern ramp for operating small boats, and the cargo volume and payload to deliver a small assault force with fighting vehicles to a roll-on/roll-off port facility. The ship is easy to reconfigure for different roles, including anti-submarine warfare, mine countermeasures, anti-surface warfare, intelligence, surveillance and reconnaissance, homeland defense, maritime intercept, special operations, and logistics, all by swapping mission-specific modules as needed.
The LCS program is still relatively new as of 2018 with only ten active ships, but the navy has announced plans for up to 32 ships. The navy has announced that a further 20 vessels to be built after that will be redesignated as 'frigates'.
A special case is the USS Constitution, commissioned in 1797 as one of the original six frigates of the United States Navy, and which remains in commission at the Charlestown Navy Yard in Boston. She serves as a tribute to the heritage of the Navy, and occasionally sails for commemorative events such as Independence Day and various victories during the War of 1812. Constitution is currently the oldest commissioned warship afloat (HMS Victory, though older and also in common, is in permanent drydock).
