If friends are visiting Malibu for the first time, or just want to take a day trip from LA, this is usually what I recommend. It's pretty casual and adaptable to do with or without kids, or solo too. It's also doable year-round, even when it's not warm enough to spend a whole day at the beach. Enjoy!
Park at the very end of the Pt Dume State Beach parking lot (towards the bluffs), then walk up the path and around the headlands. If you're up for a longer walk, take the stairs down to Big Dume and walk along the beach. https://maps.app.goo.gl/dnGzbTEGKxsdm9Au9