With just 18 days until the New York Islanders open their first season in Brooklyn, team owner Jonathan Ledecky is personally calling prospective season ticket holders to help close the sale, The Post has learned.

“That’s a leading indicator they have issues selling tickets,” a sports industry source said.

However, a Barclays spokesman said that the team is ahead of its initial goal of selling between 7,500 to 8,000 season tickets.

After 43 years at Nassau Coliseum on Long Island, the Islanders are counting on fans to follow them to Brooklyn’s Barclays Center to start their season on Sept. 21.