Orlando Bloom is meeting some of the locals over in Italy … but we’re talking about life under the sea … ’cause he went snorkeling with his son, and a very cheeky mystery woman.

The “Pirates of the Caribbean” star enjoyed a snorkel session Sunday … with his son Flynn and a stunning woman in a skimpy bikini. No whales in Italian waters, but plenty of whale tails on this occasion.

Orlando’s snorkeling outing appears to be part of his co-parenting yacht adventure with his ex Katy Perry … on the same day, they were spotted on a mega yacht with Jeff Bezos and Lauren Sanchez Bezos in Capri.

Flynn here is from Orlando’s previous marriage to Miranda Kerr … and Orlando’s reps say he’s going to co-parent his 4-year-old daughter Daisy with Katy after their recent split.

So far, the co-parenting thing is off to a great start … though it helps to be on a yacht cruising the Italian coast.