The intense pressure that accompanied Phelps every time he stepped on the deck during the height of his career has dissipated. He appeared relaxed, smiling and joking with longtime coach and friend Bob Bowman at his side.
"I'm doing this because I want to," he told a gaggle of reporters and TV cameras. "Nobody is forcing me to do this or that."
Bowman and Phelps frequently clashed during his career, with Phelps rebelling against his coach's hardnosed style.
"He's much happier doing the training," Bowman said. "When he first came back he was so out of shape."
"Easy," Phelps scolded playfully. "Sugarcoat it at least."
At his heaviest, Phelps weighed 225 pounds. He competed at 187 in London, and last week was down to 194.
"It took a while to get to a point where OK, he could do this in public," Bowman said.
Phelps isn't worried about marring the legacy he built over four Olympics.
"I'm doing this for me," he said. "If I don't become as successful as you all think I would be or should be and you think it tarnishes my career, then that's your own opinion. I'm doing this because I want to come back and I enjoy being in the pool and I enjoy being in the sport of swimming."
Phelps was noncommittal about whether his comeback would lead to swimming in the 2016 Rio Olympics, although he admitted that if he wants to compete at the highest level, he has to be ready by this summer.
"I am looking forward to wherever this road takes me," he said.