The rare photo of the girls show them from the back, dressed in swimsuits and playing with toys on a blanket.
Shepard, 43, previously opened up about his daughters’ sense of adventure, telling Seth Meyers of his family of four, “We go to the sand dunes on all of our vacations to go off-roading.”
Meyers then held up a photo Shepard shared to Instagram in November, of a dune buggy in the air, and asked if his girls join their dad for the fun.
“I have car seats strapped to the back,” the CHiPs actor joked, continuing, “I strap their car seats into the five-point harness and then the car seats have a little harness and they have these cute earmuffs.”
Earlier this month, Bell chatted with PEOPLE about how Delta is “incredibly destructive” and “wants to touch everything” at the moment.
The best related advice she’s gotten? “One mom told me, ‘Let her touch things with one finger. That way it’s exciting for her,’ ” recalled the Veronica Mars star. “So if she wants to touch a vase that I know she shouldn’t, I say, ‘Oh, I want to touch it too. Let’s use one finger!’ “
Along with keeping her household unscathed, Bell said the rule also helps give her children a sense of control. “It makes them feel like they have a little bit of a choice,” explained the star.