The forwards won the Stanley Cup four consecutive times with the Islanders from 1980-83.
Tonelli, who wore No. 27 while playing eight seasons for the Islanders from 1978-1986, will have his number retired prior to the game against the Detroit Red Wings on Feb. 21.
Tonelli is eighth in Islanders history with 544 points (206 goals, 338 assists) in 594 regular-season games, and tied for sixth with 83 points (28 goals, 55 assists) in 113 Stanley Cup playoff games.
Anders Lee, the Islanders captain, wears No. 27 and has the blessing of Tonelli to continue doing so.
"I have spoken with current Islanders team captain Anders Lee, and from seeing the tremendous leader he is, I told him that I would be honored if he continues to wear our number until the end of his career," Tonelli said.
Goring, who was acquired by the Islanders in a trade from the Los Angeles Kings on March 10, 1980, and helped New York win the first of its four consecutive championships that spring, will have his No. 91 retired prior to the game against the Boston Bruins on Feb. 29.
"I'm extremely honored to have my number retired by the New York Islanders," said Goring, who won the Conn Smythe Trophy as Stanley Cup Playoff MVP in 1981 and is an Islanders TV analyst. "I came to the Long Island community back in the 1980s, and since then I have made it my home. Some of the greatest accomplishments of my career happened with this fan base, and I can't wait to share this night with them as well."
Goring had 195 points (87 goals, 108 assists) in 332 regular-season games with the Islanders, and 68 points (28 goals, 40 assists) in 99 playoff games.
Tweet from @91Butch: Today has become one of the best days of my https://t.co/2o3VDvTIbI have my number retired is beyond expression and belief.The response from fans and friends as well as family is overwhelming.February can not come fast enough.Thanks to everyone for the kind words
Denis Potvin (No. 5), Clark Gillies (9), Bryan Trottier (19), Mike Bossy (22), Bob Nystrom (23) and Billy Smith (31) previously had their numbers retired by the Islanders. In addition, former coach Al Arbour and former general manager Bill Torrey have banners saluting their achievements next to the retired number banners at Nassau Coliseum and Barclays Center, New York's home arenas.
"It's a huge honor for [Tonelli and Goring]," Lee said. "We're all really excited for them. That's something you dream about as a kid, having someday your jersey being retired, and those two couldn't be any more deserving. They were such key parts to that dynasty and really set the traditions and what it means to be an Islander."
