The Younger actress was dressed in a peach floral blouse, cut-off jeans and beige flats. She helped Luca take off his shoes before playing in the sand.
Last week, Duff and her ex-husband Mike Comrie vacationed in Maui, Hawaii with Luca and other members of their families.
The singer shared multiple photos of their vacation.
Duff filed for divorce in February of 2015, after five years of marriage. The ex-couple remain close and co-parent their son amicably.
Image Credit; Fame/Flynet