One big happy family!

Ben Affleck and Jennifer Garner know how to balance work and family time. Garner, 40, brought their three kids -- daughter Violet, 6, Seraphina, 3 and son Samuel, 4 months, to Puerto Rico to join dad Affleck, who's on location filming Runner, Runner with Justin Timberlake, 31.

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The beautiful family hit the beach Monday and the stars showed off their impressive beach bods. Affleck, 39, revealed

The actress splashed around in the water with her daughters before grabbing her sundress cover-up to go for a walk with her baby boy. Little Samuel was kept shielded from the sun with a large hat as he watched his siblings play from his mom's hip.

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When Affleck isn't spending quality time with his family on the beach, he's been hard at work on his new film with costar Timberlake. Runner, Runner is about a businessman who gets caught up in the world of offshore online gaming.

But the father-of-three would still like to have one more child with his wife!

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The couple toasted their seventh anniversary on June 29 and a source recently told Us Weekly their debating having another child. "Jen is happy with three now that she has a boy," the pal said. "Ben wants four."

This article originally appeared on Jennifer Garner Unveils Sexy Post-Baby Body in Retro Swimsuit!