No areas or times to comply with (other than dusk or dawn, which is when the landlord usually collects his rent... :) ) But always good to get local knowledge in any area re conditions you may not be familiar with. Especially true if you don't have much or any experience dealing with surf

If you are in Santa Monica, check out the Tower 26 group that swims at, conveniently, Tower 26 in Venice/SM area. Not aware of groups that swim in Malibu, although LA Tri sometimes swims at Zuma (that's a good place to check up on conditions, especially if you don't have any surf entry experience)

There are additional groups further south, I know some folks drive down from the SM area. Saturday morning is the SMOG group in Redondo Beach, circuit workout, Lifeguard stand A near Topaz jetty, 8 am. Sunday morning is the LA tri group at Manhattan Beach pier 8 (?) am, walk down beach and swim 1, 1.5 or two miles back.

If you decide to swim alone, always let a lifeguard or someone else know where/when you are going.