The New York Islanders will soon be putting their failed Brooklyn hockey experiment on ice — as state officials have approved a new arena at Belmont Park that will let the team skate back to Long Island, sources told The Post.

Gov. Cuomo is expected to announce Wednesday that the Islanders won the bidding contest to build an 18,000-seat arena at the race track — where the team hopes to improve on their Barclays Center attendance numbers, which reached the lowest in the NHL a little over two years after their move the Brooklyn.

“This is great day for fans of the Islanders and Long Island,” said one government source. “Brooklyn never did work out.”

The Islander proposal — which beat out a bid by Major League Soccer’s New York City FC — will include a 435,000-square-foot retail hub, a 200-plus-room hotel and other amenities. It will all go up on under-used parking lots adjacent to the famous track in Elmont, LI.

There is no time table yet announced for completion of the project, though sources said the Islanders are expected to play at the Barclays Center through next season, and possibly play at Nassau Colosseum after that, until their new home is built.

Teaming up with the Islanders on the project will be Sterling Project Development, a real estate firm headed by the Wilpon family, which owns the Mets and the Oak View Group, whose investors include James Dolan’s Madison Square Garden Co.

Although the Islanders own one of the NHL’s top home records since coming to Brooklyn in 2015, their fan base has remained quite sour about the team leaving Long Island.

The Islanders have been averaging only 11,642 fans per game, which was not just worst in the NHL but 3,692 less than their final season at Nassau Coliseum.

Former team owner Charles Wang moved the team to Brooklyn only after failing to get a new arena built on Long Island, which the team had called home for 43 years.

Nets owner Mikhail Prokhorov’s Brooklyn Sports & Entertainment, which runs Barclays Center and Nassau Coliseum, wants the Islanders out of Barclays Center as soon as possible. Prokhorov believes Barclays Center could see a cash windfall if it replaced the Islanders by bringing in more concerts and other attractions, sources said.

Representatives for the Islanders and NYCFC did not return messages. Officials for Empire State Development Corp., who oversaw the bidding on the Belmont site, and Barclays Center declined comment.

The Post first reported that the Islanders and Barclays Center were looking to opt of their 25-year lease in February 2016 — less than a year into the deal.

Barclays Center was originally retrofitted to accommodate hockey, but star architect Frank Gehry’s spectacular design was scrapped in 2009 to cut costs. Ellerbe Becket and SHoP Architects co-designed the sleek glass-and-steel, clamshell-like Barclays Center about 200,000 square feet smaller than the original Gehry design.