St Tropez has no train station — the nearest is Saint-Raphaël, about 35 km away by road and considerably further by the twisting Corniche road. This is deliberate, and it keeps things exclusive, but it also makes arrival unnecessarily complicated in summer.
By ferry is the fastest and most pleasant option from mid-April to October. Bateaux Verts and Les Bateaux de Saint-Raphaël both run regular services from Saint-Raphaël and Sainte-Maxime. The crossing from Sainte-Maxime takes about 15 minutes; from Saint-Raphaël about 50 minutes. This avoids the worst of the D98A congestion entirely.
By bus (Var Lib network) from Saint-Raphaël or Toulon — buses run year-round but are slow and infrequent. The journey from Saint-Raphaël takes 1.5–2 hours in summer traffic.
By car is possible but inadvisable in summer. If you must drive, the D98A from Sainte-Maxime (via the coastal road) or the N7 inland are both subject to severe congestion from mid-June to mid-September. Parking in town is limited and expensive; use the park-and-ride at La Foux and take the navette shuttle.
The nearest airports are Nice Côte d'Azur (90 km) and Toulon-Hyères (60 km). Helicopter transfers from Nice are available for those with appropriate budgets.