The Obelisk on the Border of Saint Martin The treaty of 1648 still applies today; it allows goods and people to move freely between both parts of the island.

Yes, you can cross freely between the French side (Saint-Martin) and the Dutch side (Sint Maarten) of the island, as there is no physical border control or passport checkpoint. The island is unique in that it is the smallest landmass in the world shared by two sovereign nations, yet the boundary is entirely open to visitors and residents alike. You will often see a simple sign or a monument on the side of the road marking the transition between the two territories, such as "Bienvenue à la Partie Française." This open-border arrangement has existed since the Treaty of Concordia in 1648. While you are technically entering a different jurisdiction—the French side is an Overseas Collectivity of France (part of the EU), and the Dutch side is a constituent country of the Kingdom of the Netherlands—the lack of customs or immigration checks makes it feel like one unified island. This ease of movement allows travelers to have breakfast in a French bakery in Marigot, spend the afternoon on a beach in Philipsburg, and enjoy dinner in the gourmet capital of Grand Case without ever showing their passport after their initial arrival at Princess Juliana International Airport (SXM) or the Grand Case Espérance Airport (SFG).