The Islanders finally got some offseason business done, signing their three restricted free agents — Noah Dobson, Alexander Romanov and Kieffer Bellows — to extensions, the team announced Monday morning.

Dobson and Romanov both signed for three years, with Bellows agreeing to a one-year deal. Dobson’s deal is worth $4 million per year while Romanov’s deal is for $2.5 million per, an industry source told The Post. Dobson’s deal sets him up to hit restricted free agency a second time before he turns 27, when he can become an unrestricted free agent under the CBA. Bellows’ contract is for $1.2 million, according to CapFriendly.

Though it was never seen as a strong possibility that any of those three would leave Long Island this summer, actually getting the deals done and announced will be a bit of a relief for the Islanders, as the team’s offseason has gone so poorly to date.

Romanov, who came over in a draft-night trade with the Canadiens, is Lamoriello’s only new acquisition thus far over the summer. As a 10.2(c) restricted free agent, he didn’t have the rights to negotiate with any other teams. His expected defensive partner Dobson, though, did. And following a breakout season, retaining him was a high priority.

As the numbers for all three players come in, the Islanders’ cap space situation will also become more clear. They had spent the summer with approximately $11 million in room, but also with the knowledge that most of that would go towards these three players.