10/01/2013 at 09:35 AM EDT
Talk about making a splash.
On Saturday, Matt Damon
, wife Luciana and a large group of family members (26 in all) lounged poolside at the Fontainebleau Miami Beach.
The group enjoyed a leisurely lunch at La Cote, the hotel's ocean view Mediterranean restaurant, where they ate, drank and played with the children. On the menu? Chicken Caesar salad, lobster thermidor, grilled vegetable platters, seared haloumi, lentil salads, fried calamari, conch ceviche and a variety of kids' food (including special milkshakes). Pitchers of Margaritas and pina coladas flowed freely as well.
A source tells PEOPLE the Elysium
star – who reserved a private section at the upper level – and family were celebrating Luciana's mother's birthday.
"The entire group was extremely kind," staffers say, adding that the whole family had "a fabulous time."
Damon was also a very generous tipper. "He left an extra $500 on a check that already included gratuity," the source adds.
Luciana – who is originally from Miami – and Damon may have been spending some last moments at their waterfront Miami Beach estate, as they recently put the house on the market for $20 million
– Becky Randel