When it comes to beach etiquette, there is a way to act and a way not to. Even the great outdoors has rules, it turns out. Problem is, they're mostly unwritten and often ignored.

The general rule: Leave nothing on the beach except footprints. Otherwise, others end up paying for your messy habits.

"People from the other side of the island will party on the beach or in the parking lot," said Treene Froiseth, lifeguard captain for the leeward coast of O'ahu. "People who live there end up cleaning it up."

Some taboos are less obvious. Digging deep holes in the sand and leaving them unfilled is discouraged because they are a hazard to walkers.

"The beach is such an informal, relaxed kind of place," said Mainland etiquette expert Honore McDonough Ervin, co-author of the etiquette guide "Things You Need to Be Told." "People who might normally have good manners ... all good reason just flies out of their head and they do things that are offensive to others."

Some no-nos are explicitly listed on lifeguard stands or beach signs: Alcoholic drinks, dogs, picnic lunches, ball-playing and aerial disc-throwing, for example, are banned on many beaches, although enforcement varies.

Others are obvious enough: not crowding other beachgoers, kicking up sand around people, playing music loudly or leaving trash or cigarette butts.

"The cigarette butt is particularly offensive, not just because it's ugly, but because the filters — which are filled with contaminants — get into the food chain," said Cindy Zipf, executive director of Clean Ocean Action, an environmental group based in Sandy Hook, N.J. "They look like small crabs or fish to gulls, and they get eaten."

Beach umbrellas, too, can be hazards when not well-anchored.

Playing loud music from your car also can be both irritating and is potentially dangerous. "When you've got two cars grinding two different tunes," said Froiseth, "you can't hear yourself think or hear anyone yelling for help."

Not keeping tabs on boisterous small children is rude, too, especially if they are kicking sand on or otherwise bothering other sunbathers, Ervin points out.

"You should keep kids on a fairly tight leash, not just because they're bothering others but (for) their own safety," Ervin said.

On beaches where crabs and creatures outnumber swimmers, environmentalists have a gentle reminder: No poking, prodding or removing the creatures from their natural setting.

Feeding birds is another faux pas, one almost universally reviled by beach regulars.

That's bad manners. But if life's a beach, rude behavior is to be accepted. Rude people, said Hilka Klinkenberg, founder of Etiquette International, "don't suddenly become mindful people on the beach."