The first thing to notice is that Saint Martin is a two-in-one destination. What's the deal? It is due to the island of Saint Martin being divided in two. One half is French and is known as Saint Martin, while the other is Dutch and is known as Sint Maarten. This is crucial to understand since, depending on which side you wish to visit, you will need to investigate the visa requirements. After all, we're talking about two distinct countries with distinct visa regulations.
In terms of the French portion of Saint Martin, we need to look at the visa policy of the French overseas territories. Fortunately, the visa process is lax, so practically everyone may visit the French side of the island. This visa policy, like any other, contains a list of visa-exempt nations. You should be aware of certain unusual scenarios. If you are a German citizen, for example, you may enter and remain in Saint Martin permanently since your country of origin is a member of the EU. In addition to EU nationals, citizens of Andorra, Iceland, Liechtenstein, Monaco, Norway, San Marino, and Switzerland are permitted to reside in Saint Martin indefinitely. The visa policy also includes a list of countries whose inhabitants are permitted to remain in Saint Martin for durations ranging from 3 to 6 months, depending on nationality. Before you begin arranging your trip to Saint Martin, you should familiarize yourself with the visa policies of French overseas territories. If your nation is not on any of the lists, you must travel to the closest French embassy and request for a visa to Saint Martin.
Another thing to keep in mind is that a Schengen visa will not allow you to enter Saint Martin. Saint Martin is not a member of the Schengen Area Agreement, although France is. As a consequence, you'll need to apply for a Saint Martin visa.