The Alta class was built by KværnerMandal during 1996 and 1997, while the related Oksøy class was built in 1994 and 1995. A total of 9 vessels were built, 5 minesweepers and 4 minehunters. The catamaran hull is built in a fibre-reinforced plastic sandwich of very low magnetic signature.
Two large fans located on each side create an air cushion between the two hulls and a front and aft rubber skirt, lifting the vessel, giving small drag and a high cruise speed, as well as low susceptibility to the shock of exploding mines since only a small portion of the hull is actually exposed in the water. Propulsion by water jet, again one in each hull, gives a low acoustic signature. A degaussing system gives the vessels extremely low electromagnetic signature.