Small domestic flights land at Puerto Jiménez Airport, making this the quickest access point for the Osa Peninsula from San José. Overland buses are slower but cheaper, usually routing through Palmar Norte before turning south toward the gulf.
Boats connect Puerto Jiménez with Golfito across the Golfo Dulce. They are useful if you are combining the Osa Peninsula with Costa Rica's far southern Pacific coast, but schedules and sea conditions can change, so confirm locally.