Yes, for the most part, the beach in Hawaii is a place to run free and let your freak flag fly. But bear in mind, some rules do apply when traipsing along the sand:
1. The flip flops (called 'slippers' in Hawaii) that accumulate near beach entrances are not free. They belong to people. You may, however, select from among the single slippers that are commonly washed up at the shoreline—and good luck trying to find a pair.
2. Turtles have the right of way, in the water and on the sand. Don't touch. You'll find the big reptiles on all the islands, but they are commonplace on the Big Island of Hawaii.
3. If you see a large-bellied creature on the sand—and it is not sunburned—stay back at least fifty feet. Hawaiian Monk Seals, the only mammals besides an obscure species of bat to occur naturally in Hawaii, like to sun themselves on the sand. Kauai is the island that hosts the most seals, both at wild beaches and those with lots of people. Conservation groups put a rope barrier around the animals when a report is made, but at remote beaches this is not the case.
If you are interested in wildlife (not the kind that thrives on Kuhio Avenue in Waikiki) see No Worries Hawaii, a vacation planning guide that lists beaches and trails that are best for spotting creatures in the sea, on land, and in the air.