He popped out of bed around 6 in the morning Sunday, as if it were another normal training session.
"I wish I could sleep a little longer," Phelps said. "I've been used to getting up early the last 20 years. We're going to work on getting on a little different schedule."
Phelps can start sleeping later now. He can do whatever he wants. At 27, he ended his swimming career in London as the most decorated Olympian ever with 18 golds — twice as many as anyone else — and 22 medals overall. The only thing left to do is sign the retirement papers, which will remove him from the list of athletes who must undergo regular doping tests.
"I have not officially retired yet," Phelps told The Associated Press, "but very soon I will be signing those papers and it will be official."
Phelps isn't sure what he'll do next. There will definitely be plenty of travelling. Only this time he'll see more than just the bottom of pools and the inside of hotel rooms. He wants to work on his golf game — "the proper way, not just going out there taking a couple of hacks at a little white ball." He might even take a trip to the beach, which was something he never wanted to do when he was swimming competitively.
"If I go swimming any place, it will probably be in the ocean," Phelps said. "I will actually enjoy getting in the water at the beach. I've been on a couple of vacations before, but I never wanted to get around water because I spent so much time in the water. Hopefully, I can jump in now and actually enjoy it, just splashing around with my friends."
For the most part, though, his retirement plans are a work in progress.
He's been so focused on his swimming, on making a splash at his final Olympics, that he clearly hasn't taken much time to figure out what he wants to do next. He just knows he doesn't want to swim, not competitively anyway.
"I don't even know where to begin," Phelps said. "I'm just going to take it one step at a time, one day at a time. If I want to do something, I'm just going to do it."
For now, he's mainly focused on getting some down time. He's been swimming competitively for about two decades, and he's been at the top of the sport for nearly a dozen years. There are so many things he passed up so he could focus on swimming, and though there are no regrets, there's a lot of catching up to do.
"The biggest thing I really want to do is travel and see a bunch of the world," he said.
This, from a guy who's obviously done plenty of travelling, from Sydney to Athens, from Beijing to London. But this will be different. He wants to experience what other tourists get to experience.
He got a sampling of it Sunday, hitting the town with his mum, two older sisters and a niece.
"It's fun to see parts of this city," Phelps said. "Coming over the bridge this morning, seeing Parliament and Big Ben. I had not seen that this whole trip. It's cool being able to go around and see more of it. Hopefully, in the next couple of days, I'll be able to enjoy it a little bit more. I'll have more time to go out and see London like you're supposed to."
He paused and quickly added a telling comment on the single-mindedness that carried him to such glory in the pool but deprived him of so many other things.
"I don't know how you're supposed to" see London, Phelps said. "I have a friend who lives over here. I'll ask him what to do, what to see."
Phelps had barely climbed out of the pool for the final time when speculation started about whether he would come back. He's at an age where he could easily swim in another Olympics, maybe two. His coach, Bob Bowman, said Phelps would likely have to drop some of his longer events but could still be one of the world's best in several races if he wanted to keep going.
Dara Torres, who won three silver medals at age 41 and just missed making her sixth Olympic team this year, tweeted that she's betting on a Phelps comeback.
"Anyone care to wager???" she wrote.
Phelps playfully tweeted back: "Yes I would love 2!!!"
"The competitive part of my career is over, but that doesn't mean I'm done with the sport," he said. "This sport has allowed me so many opportunities. I've had the privilege to do some of the coolest things in the world. I'm still going with my goal, to try to change the sport, to take it to a whole new level. It hasn't reached the peak that I want it to reach."
He plans to attend the world championships in Barcelona next year, and he's already promised his mum that he'll take her to the Rio Games in 2016. But before anyone gets the wrong idea, he quickly adds, "I'm not competing. I'm not competing. I'm not competing.
"I want to see what it's like being on the outside looking in," Phelps said. "It will be cool to see how people progress."
He's not at all worried about the U.S. program carrying on without him. Indeed, this was more of a team effort than the past two Olympics, which were dominated by Phelps' Herculean performances. He still won more medals than any other swimmer, but four golds and two silvers was a step down from Beijing. Even so, the Americans won 16 golds — their highest total in a non-boycotted Olympics since 1972.
Seventeen-year-old Missy Franklin captured four golds, equaling the U.S. mark for a female swimmer set by Amy Van Dyken in 1996. Allison Schmitt won three golds, plus a silver and a bronze. Fifteen-year-old Katie Ledecky nearly broke the world record in the 800 freestyle. And Ryan Lochte, who was a bit of a disappointment despite winning five medals, plans to keep on swimming.
"We have a great team right now," Phelps said.
One thing he doesn't want to do: Regain those 25 pounds he put on in 2009, when his enthusiasm for the sport waned and he wasn't even sure if he wanted to come back for another Olympics.
"I'm a person that's very goal-oriented," he said. "I'm sure I can find things to get excited and motivated for."
Follow Paul Newberry on Twitter at www.twitter.com/pnewberry1963