Original: Ferries to and from Saint Maarten are the only other real option (although the passage from St. Martin to St. Barth is often rough), unless one is arriving by private charter boats/yachts.
Simplified: Ferries to and from Saint Martin are the only other real option (although the passage from St. Maarten to St. Barths is often rough), unless one is arriving by private charter boats/yachts.