Kelvin Ewart Tarlton (31 October 1937 – 17 March 1985) was a marine archaeologist and treasure-hunter who established Kelly Tarlton's Underwater World in Auckland, New Zealand.
 Tarlton was born on 31 October 1937 in Te Kōpuru in the Northland Region of New Zealand. His parents were Elsie Alexander and Ewart Fritz Tarlton. His father was an engineer. They moved to Auckland where he went to Pasadena Intermediate School, although he spent nine months in hospital owing to a reaction to penicillin and a kidney condition. The family moved to Christchurch where he attended Christchurch Boys’ High School. On leaving school he qualified as a telephone exchange technician at the Post and Telegraph Department in 1961.
 Recreationally he was a mountaineer and joined the Canterbury Mountaineering Club. He then became a diver joining the Canterbury Underwater Club inspired by Jacques Cousteau’s movie The Silent World. His first dive was in 1956. He set a New Zealand freediving record in 1959 at Curious Cove, Queen Charlotte Sound, (depth of 24 metres). Over the next few years, Tarlton organised and took part in diving trips in places such as Wuvulu Island and Poor Knights Islands Tawhiti Rahi, moving to live in Whāngarei near the Poor Knights, which is now a marine reserve. During these trips Tarlton collected marine specimens, discovered new species, and explored and developed ways of taking photographs and films underwater.
 Tarlton became a professional diver in 1966. He worked on construction and also salvaged and explored many shipwrecks in New Zealand waters and around the world including in the late 1970s with Mel Fisher looking for treasure in the Caribbean for the Atocha and Santa Margarita (sunken Spanish galleons). In 1974 he and two others found items from the steamer Tasmania which sank off Gisborne in 1897 and in 1976 Tarlton was one of the backers of an expedition searching for treasure from the ship General Grant which had disappeared in 1866. In 1980 he was part of an international consortium searching for gold bullion in a ship believed sunk off the Netherlands in 1799.
 After his time in the Netherlands, Tarlton decided to build a new style of aquarium. The attraction was constructed in a collection of disused municipal stormwater and sewerage tanks in Auckland, and opened by Tarlton in 1985, as Kelly Tarlton's Underwater World. The design of the aquarium was innovative at the time. Prior to its construction, aquariums typically had tanks with flat glass fronts for visitors to look through. Tarlton's design, with its curved acrylic tunnels underwater that visitors go through on a conveyor belt, looking all around at the underwater life in the tanks, has been influential for many aquariums overseas. The aquarium was designed to replicate a reef zone from the Hauraki Gulf. In 2015 the aquarium still held a stingray caught by Tarlton 30 years previously.
 Tarlton is in the International Association of Amusement Parks and Attractions (IAAPA) hall of fame.
 In 2023, Tarlton was posthumously inducted into the New Zealand Business Hall of Fame.
 Tarlton died from a heart condition in 1985 only six weeks after Kelly Tarlton's Underwater World was opened.