From Ventura, Ca
Take Hwy 101 South to Calabasas, Ca. Exit on Las Virgenes Rd and turn right. Drive about 2 miles until you cross Mullholland, there's a stoplight. On your right you'll see a sign for Malibu Creek State Park, slow down and turn right at the park entrance.
Hike along Crag's Road, a dirt road. When you see a bridge over the creek, a few ways to go but all wind up by this bridge, go upstream a few hundred yards. Now here you are at Tarzan's Lagoon! It's really that easy or just follow the numerous herds of other hikers. Hint look for towels and bathing suits.
There are three spots to jump. A 5-40 foot cliff into 8 feet of water over bedrock, just jump it's deep enough. A 10 footer into varying depths of gravelly sand. A 25-40, 90 foot jump into 12 feet of water, do not land between the cliff and the big rock unless you are landing on the downstream side of the rock. It's a long, green rock under inches of water.
You guys should still check the water as sediment sometimes fill our pools.