FF(X)

	Rendering of the FF(X) frigate, based on the Legend-class cutter
Class overview
Builders	Huntington Ingalls Industries
Operators	United States Navy (projected)
Preceded by	Constellation class
Planned	50-65
General characteristics
Type	Frigate
Displacement	4,750 tonnes (4,670 long tons; 5,240 short tons)
Length	421 feet (128 m)
Beam	54 feet (16 m)
Draft	22 feet (6.7 m)
Speed	28 knots (52 km/h; 32 mph)
Range	12,000 nautical miles (22,000 km; 14,000 mi)
Complement	148
Sensors &; processing systems	AN/SPS-77 3D air and surface search radar
Electronic warfare; & decoys	AN/SLQ-32(V)6 electronic warfare suite; 2 × Mk 53 Nulka Decoy Launcher System;
Armament	Flight I; 1 × BAE Systems Mk 110 57 mm gun; 1 × 30 mm gun; 1 × 21-cell Mk 49 RIM-116 Rolling Airframe Missile launcher; Up to 16 × Naval Strike Missile launchers or modular containerized payloads;

FF(X) is the designation for a class of frigates intended for the United States Navy based on the National Security Cutter (NSC) or Legend-class cutter in service with the United States Coast Guard. The program was announced on December 19, 2025, and the ships will be built by Huntington Ingalls Industries.