However, there is lingering scepticism considering this is McGregor third retirement announcement in four years.
In April 2016, McGregor tweeted: "I have decided to retire young. Thanks for the cheese. Catch ya's later."
Then in March 2019, following his loss to Khabib Nurmagomedov at UFC 229. he tweeted: "Hey guys quick announcement, I've decided to retire from the sport formally known as Mixed Martial Art today. I wish all my old colleagues well going forward in competition. I now join my former partners on this venture, already in retirement. Proper Pina Coladas on me fellas!"
It's understandable some UFC fans are therefore quick to question the validity of Sunday's announcement.
McGregor returned for a welterweight bout with Donald Cerrone at UFC 246, where he was awarded Performance of the Night. He has also recently shown interest in a rematch with Nurmagomedov.
The Irishman boasts a 22-4 professional record, and is a former UFC Featherweight champion.
UFC President Dana White has already said McGregor is next in line for a title shot at the winner of lightweight champion Nurmagomedov's bout with Justin Gaethje this summer.
The UFC's schedule is in upheaval due to the coronavirus pandemic, but McGregor was expected to get his title shot later this year, and he recently had been talking to White about taking another fight even earlier. Earlier this week, McGregor posted photos and videos of himself training for fights.
White was still willing to take McGregor's retirement announcement at face value — at least publicly — when he learned about it at his news conference following UFC 250 in Las Vegas.
"If Conor McGregor feels he wants to retire, you know my feelings about retirement," White said. "You should absolutely do it. And I love Conor. ... There's a handful of people that have made this really fun for me, and he's one of them."
Retirements are a time-honoured device for gathering attention and increased bargaining power in combat sports. From Muhammad Ali and Floyd Mayweather to Tito Ortiz and Chuck Liddell, countless champions of boxing and MMA have gone back on their solemn announcements whenever need or ego brought them back to the sport.
The loquacious McGregor has long proven that his pronouncements can't be taken as gospel truth. Earlier this year, McGregor "accepted" future fights against former UFC middleweight champion Anderson Silva and long-retired boxing superstar Oscar De La Hoya with little reason to think they will ever happen.
- With AP