Penarth Marina occupies the historic basins of the old Penarth Docks, which closed in 1963 and were redeveloped for leisure use. A yacht lock was built in 1986 and the marina opened in 1987, offering over 300 berths for yachts and small boats.

It sits adjacent to the River Ely and Cardiff Bay, close to the Cardiff Bay Barrage, whose completion in 1999 created a freshwater impoundment that improved conditions within the marina.

Recognised as Cardiff Bay's premier berthing location, the marina holds a five Gold Anchor accreditation from the Yacht Harbour Association, a European Blue Flag, and membership of TransEurope Marinas.

A full boatyard is on site, and the Victorian town of Penarth as well as Cardiff city centre are both within easy reach.