One of the best kept secrets on the island of St. Martin is Happy Bay Beach, a nearly deserted, remote beach that takes some effort to get to but is definitely worth it.
How to get there: ***Note: these directions are based on the driver coming from the Dutch side of the island. If you are coming from the French side, the first turn is a left rather than a right***
In your car, follow the signs to Marigot and/ or Friar's Bay Beach. At the Bleu laundromat (it literally is a big blue building), take a right and follow the dirt road to the end, where you will find a cement- bottomed gate. Park your car to the right of the gate. You'll see a dirt path to the right and a small footpath through some plants that goes directly around the fence. Take the footpath. Don't worry, it's not private property, and you won't be trespassing. Stay on the paved road until you see houses in front of you, and then take the dirt path (don't continue on the paved road). Continue to follow the dirt path until you see a giant stone Buddha head in a clearing to your right- I promise I'm not making this up- and then make a left to cut through the grass, onto the sand, and follow the sand straight to the beach. The walk is a little over a quarter mile and took us about 10 minutes to make.
What to expect once you get there: Happy Bay Beach is almost always less crowded than any other beach you will find. When we went, we were 5 of about 12 people on the beach. The volcanic rocks create natural tide pools, and the crystal clear water is wavy. The tide is a little strong, but nothing that can't be handled if you stay where you can touch the bottom (if you're not a strong swimmer). If you walk to the left (as you're looking at the water) the beach becomes more and more populated. People with younger children, be warned, the left side of the beach is a nude beach. The water is perfect for swimming, warm and clear with no seaweed and the rocks provide a perfect place for photo ops.
In short, Happy Bay Beach is a little slice of undisturbed paradise that is completely worth seeing if you can make the walk. Although it takes a bit of effort to get to, being almost completely alone on a world class beach is an experience not to be missed.