HMS Ulster was a U-class destroyer of the Royal Navy of the United Kingdom that saw service during World War II. She was later converted into a Type 15 fast anti-submarine frigate, with the new pennant number F83. Ulster was the second vessel in Royal Navy history to have that name. With funds gathered through a Naval Savings Campaign in 1942 known as Warship Week, the ship was adopted by the civil community of Ulster's County Down.