The 14-time Olympic gold medalist still has a few important events to train for, most notably the world championships in July and, of course, the 2012 Olympic Games in London.
After that, Phelps will almost certainly put his swim suit in a drawer, toss aside his goggles and look for something else to do.
"It's weird to think about it. My mom and I joke about it all the time," Phelps said. "She says, 'I'm still not retired, and you're going to retire before you're 30."' Yes, but few can claim to have worked so hard for so long at the same job.
"If I retire at the age of 27, that's 20 years in the pool," Phelps noted. "That's a long time to be staring at the black line, four to five hours a day." In a recent interview with The Associated Press, Phelps spoke about life after swimming and the importance of ending his days in the water with, well, a splash.
"There are things I still want to do in the pool," he said. "I'm making steps in the right direction. But there isn't much time left. We're getting to the end of the road, where things need to start happening now." Phelps is coming off a disappointing performance this month at the Michigan Grand Prix, where he was defeated in the 200-meter fly. It marked the first time in nearly a decade he lost in the finals of that event.
"I wasn't too pleased with what happened there. It's frustrating, losing the streak I had in 200-fly," Phelps said. "That was a streak I wanted to keep throughout my career. I think it was a good thing for me to have now, something I can use as a wake-up call heading into worlds.
I will use it as fuel and motivation to be in the shape I want to be in - and need to be in - next time I compete." Phelps will spend the next few months training for the world championship in Shanghai, but intends to make some time to promote a new video game, XBox Kinect's "Push The Limit," which enables the player to race against Phelps in a variety of events.
The game, scheduled for release next month, is another facet of Phelps' quest to bring swimming into prominence.
"I played video games growing up, Tiger Woods, Madden, and I thought, 'Maybe one day we'll be able to have a swimming video game,"' Phelps said. "Being able to have that opportunity, especially on Kinect, I think it's kind of cool. It's all you doing all the motions. It's realistic, it's not cheap, it looks good. ... And it's my own video game."
Phelps has attached his name to many a product since winning a record eight gold medals at the 2008 Olympics.
All that gold and fame won't help him in Shanghai against upgraded competition geared to bring him down.
"I'm a lot better than last year, but everybody else is a lot better than last year, too," he said. "This is the world championships. This is the year before the Olympics.
This is where everything needs to happen. I feel a lot better now than I did a month ago, but would like to be better than I am now.
"But I'm also somebody who's never satisfied, so it's kind of frustrating." Phelps has outlined an itinerary of four individual events and three relays in China. If he fares well, then that might be his planned schedule in London next year.
"It all depends on what happens this summer. If I'm able to swim a good program, a strong program, and we feel confident about it going into the Olympic trials next year, then that will be the event schedule that I'll swim," he said. "But we can add or subtract and see what happens. We just have to make sure we're at our peak this summer so we'll know what we need to do get me ready for trials and hopefully the Olympics." His life still revolves around competitive swimming, but all that will change after he emerges from the pool for the final time in London.
"After I retire, I want to work more with my foundation, I want to work more with my swim schools and try to promote swimming countrywide and worldwide," Phelps said.
"Those are passions that I have, being able to work with kids." Here's one thing he won't do: Become a swim coach.
"No, no. I could not coach. I don't know if I have the patience to coach," Phelps said. "I see what I put my coach (Bob Bowman) through, and if there was a kid that I was teaching that did the same stuff, I'm not sure how I would react. Now I see why he has gray hair. I've put him through so much stress over the last 11, 12 years."
The Bowman-Phelps tandem is gearing up for one last push, and the star swimmer intends to attach an appropriate ending on a spectacular career.
"Every time I've put my mind to something I've been able to accomplish it. That's something that I want to finish with," Phelps said. "There are a few things I want to accomplish that I think are very doable, and if I do that, it doesn't matter how many world records or how many gold medals, how much money you make.
If I can say I've done everything I wanted to do, I can say I feel like my career has been success. At the end of the day, that's all that matters."