A new luxury hotel is set to open 40ft under water off the shore of a private island in Fiji.

Located in a lagoon, Poseidon Undersea Resort will feature 25 suites under water and 58 island villas above water.

The project is the brainchild of L. Bruce Jones, CEO of US Submarines.

The underwater resort will house a restaurant, bar, gym and an underwater wedding chapel.

Above the water there will be a spa, tennis courts and a nine-hole golf course as well as a range of restaurants and bars.

The resort will be accessible via an elevator from the shore of the island.

Guests will also have access to four personal submarines provided by the resort as well a 16-passenger submarine for trip to nearby reefs.

A thick acrylic window will envelop 70 per cent of the guestrooms, promising unparalleled views of the abundant sea life.

The official opening date has yet to be confirmed.