If you want a quieter beach than the madness of Ogunquit, then come to Drake's Island beach, quieter, more locals and very laid back, I spent a whole day here by myself.
Kennebunkport, Wells, Ogunquit and York are all side-by-side seaside communities along the Maine coast and they all have their own beaches as well. It really depends on what you're looking for but if you want a locals-only beach then this would be it.
Also if you plan on swimming and not just dipping in quickly, try to find a spot on the estuary side as opposed to the ocean side, the water is easily 20 degrees warmer on the estuary side.
Parking here is at about $5 /30 minutes and paid by machine and credit card only. read more