Charlie Sheen looks like he's having a blast with ex wife Denise Richards and their two girls Sam, 7, and Lola, 6.

The foursome were all smiles while swimming with the dolphins at an undisclosed tropical location. What a holiday vacation!

Sheen, 46, posted the above photo and the following:

    "Just when we thought the trip couldn't get any better... we met Nuna..!!"

We're assuming "Nuna" is the dolphin's name. Adorbs!

Denise's baby daughter Eloise, not with the family on this excursion, is also on vacation with them. Definitely a Christmas to remember!