Legally there are none but the photos is not enforced at Kehena Beach and at Both are clothing optional beaches hawaii you will nude people wearing swimming suits as well as people naked.
Beach 69 has changed a lot since they fixed the road and put in facilities.
topless and nude beaches - Kailua-Kona Forum
Last I went I didn't see anyone without clothing, but then I wasn't looking. Actually it is not technically illeagle to sunbathe nude in Hawaii. The state supreme court ruled on hawaii and said unless you intentionally try to affront someone by exposing yourself there is no law prohibiting you from nude sunbathing. Having said that I would stick with the traditional beachs such as Kehena Photos where nude has been clothing optional for a long time.
topless and nude beaches - Kailua-Kona Forum - TripAdvisor
Kehena Beach is a black sand beach. It is a bit of a hike down a cliff beach there are steps cut into the face so it beach not that difficult. The worst problem is car break ins there from time to time so just don't leave anything of value in your car if you choose to go.