Le Stepdad in training?

On Saturday, Olivier Martinez ditched his love Halle Berry for some quality playtime at the beach in Malibu -- with Nahla!

The handsome French actor, 45, hit the sand carrying Nahla, Berry's adorable 3-year-old daughter with her ex Gabriel Aubry.

Although Berry, 44, was nowhere in site, Martinez beamed as he frolicked with his love's only child -- and Nahla grinned and giggled as Martinez swung her above the wet sand and crashing waves.

After ending her four-year relationship with Aubry in April 2010, Berry and her Dark Tides costar stepped out as a couple last September.

But Berry and model ex Aubry remain locked in a battle over Nahla. In late June, Berry's lawyer filed new papers in an L.A. court accusing Aubry of child neglect and violating their custody agreement.