From Oyster Pond, take Rue de Coralita north along the coast. Once you come to the undeveloped stretch of coast you will come to an obvious turn out right next to the water. Park there and walk the short distance down to the water's edge.
There are quite a few small islands off the eastern coast where it is undeveloped.
There's an undeveloped part of the coast on the eastern side of St. Martin -- the water is shallow enough to wade out to them where there are abundant photo opportunities for the landscape photographer.