While both are prestigious islands in the Caribbean, Mustique and St. Barts are not particularly close to one another in terms of a quick boat ride. St. Barts (Saint Barthélemy) is part of the Leeward Islands in the northern Caribbean, while Mustique is part of the Grenadines in the southern Caribbean. The straight-line distance between them is approximately 364 miles (585 kilometers). To travel between the two, you would typically need to take a private charter flight, which takes about 2 hours and 15 minutes, or a series of commercial hops through regional hubs like St. Maarten or Barbados. Because they are in different island chains and separated by several other nations (including St. Kitts, Antigua, and St. Lucia), they offer very different vibes: St. Barts has a distinct French chic atmosphere, while Mustique is a private, secluded estate-style island under the flag of St. Vincent and the Grenadines. They are "neighbors" only in the sense that they both cater to high-end luxury travelers within the broader Caribbean region.