Katy Perry and Orlando Bloom seem to be off to a great start in their new relationship dynamic … because they’re making the co-parenting thing look easy … with an assist from a mega yacht.

The exes were spotted together Sunday on a big boat sailing along Italy’s Amalfi Coast … the first time we’ve seen them together since we first reported their split.

Katy slipped on a black bikini and Orlando was shirtless aboard a floating paradise … they played with their 4-year-old daughter, Daisy Dove, and mingled with Jeff Bezos and his new wife, Lauren, who seemingly came aboard for the day.

Katy missed Jeff and Lauren‘s big day in Venice — she was touring in Australia — but now she’s caught up with them in Italy … and this may explain why Orlando wasn’t looking to hook up with anyone at the wedding.

KP and OB broke the silence on their split Wednesday … their reps said they’ve slowly shifted from romance to coparenting and planned to be “seen together as a family,” and they’re clearly living up to that statement.

Katy and Orlando left the yacht briefly … heading to shore with Daisy Dove for some ice cream and shopping … and they were all smiles on dry land too.