Nude Beaches in Hawaii

Yes there are beaches that are considered 'nude' by the locals, no it is not legal. Most of the beaches that are considered nude are way off the beaten path, and only found by people wishing to go without their clothes. If you do decide to go to one of these clothing-optional beaches, you most likely will not be harrased by the police - they have much better things to do with their time, but they have been known to ticket offenders if someone complains.

Most beaches in Hawaii do uphold a standard of wearing clothes, but you may see quite a few thongs that make you wonder, even right on jam-packed Waikiki Beach.
Big Island Nude Beaches
# Kehena Beach

Located in lower Puna, this beach is a hangout for the local 'counter-culture' folks (wiccans, new-age hippies, and anyone who prefers to live without modern technology such as electricity) plus the occasional adventurous tourist who can find it.

It is a black sand beach with wicked riptides (there are occasional drownings here) and a steep-descent trail. It is more for hanging out and maybe body-surfing than swimming.

Directions to Kehena Beach
Follow Highway 130 past Pahoa almost to the lava flow. Take a left onto Highway 137 before the road dead ends into the lava and the beach will come up on your right. There are no signs - just look for the parking pull off with ocean views on your right. The beach is down and to your left. The trail is through the vegetation off the highway.

*** Note, there used to be a nude beach on the Kona side to, but the Park Service cracked down on that and it is no longer considered one.

Some people also consider the Green Sand Beach to be nude, only because of its isolation, and the fact that no one (including police officers) can get down there without a four wheel drive or walking several miles. The locals don't consider it nude though.
Nude Beaches on Kauai

There used to be two popular nude beaches on Kauai: Secret Beach and Donkey Beach, but in the last few years the island has found nudity to be getting out of control on other beaches, and has tried to crack down on these beaches in particular. Kauai is a popular destination for families, and many people were getting offended when they went to one of these beaches and their kids saw it. Best not to try it.
Nude Beaches on Maui

Little Beach is the most popular nude beach, and a lot of people visit it. It can be downright packed at times!

You have to find Makena Beach to get there - directions are:
"Travel to Kihei staying on the Pi'ilani Hwy. until it ends in Wailea. Follow the access road (toward the resorts) to the right (seaward) to where it ends at Makena Ala Nui road. Turn left (south) on to Makena Ala Nui road and follow it for several miles until you pass the Maui Prince Hotel. Proceed for another mile and a half. On the right side (seaward) of the road, past the cinder cone (Pu'u Ola'i) is a paved parking lot (past the first dirt road turnoff to Oneuli Beach, Little Black Sand Beach). Park here and walk the rest of the way to the beach."
Nude Beaches on Oahu

There really aren't any (too many people), except for a practically gay-exclusive section of Diamond Head Beach.
Nude Beaches on Molokai

Well, most of the beaches on Molokai are very long, and very empty, especially on the south shore. They practically beg for nudism. The last time we were there we were pretty sure the only other person on the beach was naked, but we couldn't tell because he was so far away. There are no 'designated' nude beaches though.