Michael Phelps has hung up his swim cap after adding five gold and a silver medal at the Rio Olympics to his already record haul.

But now that the most decorated Olympian of all time has (really and truly) retired from competitive swimming and is back in the United States, of course the 31-year-old celebrates his first day of retirement by ... getting back in the pool.

There's nothing like being back home!! Great way to spend my first day in retirement!! @boomerrphelps @nicole.m.johnson

A photo posted by Michael Phelps (@m_phelps00) on

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Granted, it's a whole different pool now that Phelps is with his son, Boomer, and fiancee Nicole Johnson. Though considering that Phelps is probably more fish than human at this point, it's a fitting environment.

Happy retirement, Michael Phelps. The water looks fine.