Legal Question in Business Law in California

That would depend on the beach, since different beaches are under different jurisdictions, but it is pretty certain you would need some kind of permit at the very least in order to conduct business legally. Some beaches, probably the majority by miles of shoreline, are state parks. You would need to check with the state on what permits would be needed. Others are under the Federal government, either as part of a National Park or under the U.S. Forest Service. I believe the Federal government handles such things by issuing concessions. In your area (based on zip code) probably the majority of shoreline is under city government control. For city owned beaches you have to inquire city by city what permits, licenses or concessions you need to have.

Probably there is some city or county ordinance you would be violating. But such an ordinance might be unconstitutional or, in other words, you might have a constitutional right to vend, at least as to certain types of products at certain places and times. To sell food normally requires a health dept. permit. Stick to bottled water and sunscreen packets, keep a low profile; and don't carry more inventory than you can afford to have confiscated (which is probably all that would happen). In SD County you are more likely to get a ticket which would set you back a few hundred.

"On the beach" is not sufficiently specific. California beaches fall into many different classes of ownership and jurisdiction, ranging from strictly private to city, county, state and federal ownership and control. Some federal beachfront is military preserve.

In general, operating businesses of this kind in public parks of all kinds is neither strictly legal nor strictly illegal. Rather, it is closely regulated. Ypu would need not only a license for the particular type of business (and maybe several), but also a permit to conduct the business, without a fixed premises location, on park property. Many parks do grant such permits, but only a very restricted number - selling to beach visitors is not a free-for-all where anyone can apply for and receive a permit.

In addition, such a business may need health permits for its food-preparation facility and may have to take some affirmative steps to assure recycling and prevent litter.