Having been a Santa Barbara resident for many years, I have frequented all the nude beaches mentioned. Bates is just north of Rincon and south of Carpinteria, nudity was fine for years until clothed beachgoers complained on seeing overt sexual activity on the beach. So nudity there is now prohibited and is fairly rigidly enforced by the County Sheriffs office.
Summerland (Padaro Lane) is in a similar situation now. Nudity is no longer tolerated. Sheriffs regularly patrol the bluffs and have issued citations for nudity during the last year. A few regulars still go nude in the cove below the house at the northern end.
A better option for nudity is the beach just south of Sharks cove and Fernald point. This location is just north of Summerland over Ortega Hill. The beach has a seawall and big granite riprap. We've gone nude there for years without any problems.
Cemetery Beach in Montecito used to be a good nude location, but proximity to the clothed East Beach and more frequent visitation by clothed bathers has impacted its desirability as clothing optional.
More Mesa is really a nice beach. Nudity has always been accepted there. I have heard rumors of crackdowns, but most of my friends still report clothing optional status.
Just south of Goleta Pier is another secluded nude beach. You can settle in amongst the euctaltptus trees overlooking the beach and never even see anyone some days.
Juust south of El Capitan State beach is another long wide open stretch of infrequently visited clothing optional beach. Never crowded -one of my favorites.
Gaviota has several clothing optional beaches fairly close together. Secret Beach and San Onofre are near Mariposa Reino. Also just north of Refugio near Tajiguas is an outstanding nude beach not many people know about.
And of course, there are several hot springs to choose from. Big Caliente, Little Caliente, Montecito, and Las Cruces are excellent.