The island is linked primarily to the island of Saint Martin (St Marteen) witch are separated by a 10 minutes flight.
Departures are made from the Dutch side of St Marteen at Juliana airport international or from the French side at Grand case Espérance airport.
The landing in St Barths is spectacular but one of the safest in the Caribbean.
St Barths can also be reached through private companies from Anguilla, St Kitts, Nevis and other distant islands.
Most of the major international airline companies have direct flights from Europe or the US to St Marteen (Juliana airport).
You will find links to some of those companies so you can make your reservation online.
Bon voyage!