Mariah Carey Rocks Pink Swimsuit, Hangs with Kids Off Amalfi Coast

Mariah Carey's heating up the Amalfi Coast, because even the Queen of Christmas needs a summer break ... and she's taking hers in a skintight pink swimsuit.

The singer-songwriter hit the waters on the famed Italian coastline Wednesday ... donning a pink and black spandex suit with a plunging neckline that revealed her black bikini underneath.

Mimi hopped on a boat with her 13-year-old twins -- Moroccan and Monroe -- lounging around as they soaked up the European sun, and Monroe threw her arm around Mom.

The trio cruised up and down the pristine Italian coastline ... taking in the beautiful sights on the Mediterranean Sea.

It's a sweet little family vacay ... obviously, sans Nick Cannon -- the kids' dad -- who split with Mariah back in 2014.

Remember these images in about 4 months. If you're wondering where and how MC spends the reported $3 million she makes each year just off "All I Want for Christmas" ... well, here it is!

BTW ... she'll be back with a 20-city Christmas tour in November for the 30th anniversary of her album "Merry Christmas."