This list is longer than anyone can imagine. If your interest is in surfing and you find a location where there the waves are huge enough to surf all year round, then you can invest your money on a surf shop. If you love to create handmade crafts and souvenir products or at least know where to pull suppliers, then you can open a souvenir store for tourists and travellers.
If you have undergone training about liquor mixing and refreshment preparation, you can start a cocktail stand or kiosk. If you want to sell swimming apparatus, you can venture in selling assorted items like snorkels, goggles, life jackets, inflatable rafts and flippers. You can also choose to put up a business in rental beach huts. If your interest is not in these areas, you can direct your investment in shuttle service from a beach to any other points of interests.