While some parts of the country are experiencing serious sweater weather, people are still rocking bikinis down in Miami, as evidenced by Robin Thicke's girlfriend, April Love Geary!

RELATED: Robin Thicke and His Girlfriend April Love Geary Make Their Red Carpet Debut in Cannes!

The 20-year-old, who is 18 years younger than her beau, looked seriously toned while hitting the beach with the singer and his five-year-old son, Julian.

robin thicke

The model had a blast splashing around with the little boy, whose mom is Robin's ex, Paula Patton. Scroll down for more stars who are dating women young enough to be their daughters!