Excellent diving year round. You either need to swim out four hundred yards or more, or have a boat to experience the better locations. The park does not allow snorkeling, and limits the number of divers, so you need to get a reservation at http://pt-lobos.parks.state.ca.us/scuba/ where there is also a lot of information. You can see some of the more advanced dive sites at http://www.baue.org/projects/lobos/index.html