He may have quit swimming competitively, but Michael Phelps spent his first day of retirement back in the pool — albeit playing in the water with his 3-month-old son, Boomer.

The 23-time Olympic gold medalist, 31, shared a sweet pic on Instagram on Wednesday, August 17, with his fiancée, Nicole Johnson, and baby boy, captioning the photo, “There’s nothing like being back home!! Great way to spend my first day in retirement!!”

Boomer looks perfectly at home in the water, wearing a large white sunhat and blue and yellow rash guard.

While his dad was the star of the 2016 Rio Olympics in the pool, winning five gold medals and one silver and becoming the most decorated athlete in Olympic history, his son stole the show in the stands, wearing some adorably patriotic outfits and mirroring his dad’s menacing stare.

Phelps had promised reporters that Boomer would “be dressed to impress,” and he was right.

Former Miss California USA Johnson, who got engaged to the swimmer in February 2015, dressed their only child in an eye-catching succession of red, white and blue ensembles, and showed off the babe’s style (which included a Team Daddy T-shirt) on his own Instagram account.

Phelps announced his retirement on Monday, August 15, following his history-making time in Brazil.

“Done, done, done — and this time I mean it. I wanted to come back and finish my career how I wanted, and this was the cherry on top of the cake,” he told NBC’s Matt Lauer. “I’m done. I’m finished. I’m retired. I’m done. No more.”

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