The Osa Peninsula

The Osa Peninsula holds the largest remaining stretch of lowland tropical rainforest on the Pacific side of Central America, and its density of life is frequently described in superlatives, most famously in a National Geographic phrase about biological intensity that the local tourism industry has never let go of. Around half the species recorded in Costa Rica occur here, on a peninsula that is a fraction of a per cent of the country's area. Corcovado is the core, but the rest of the peninsula matters too: the Golfo Dulce on the eastern side is one of very few tropical fjords in the world, and reserves and private forest surround the park on all sides.

What you actually see

• The lowland rainforest - the last large stand on the Pacific side of the isthmus.
• Golfo Dulce - a tropical fjord, one of only a handful anywhere.
• Scarlet macaws - abundant here after near-extinction elsewhere.
• Puerto Jiménez and Drake Bay - the two bases at either end.

When to go

December to April is the dry season and the most comfortable. The wet season from May to November brings enormous rainfall and some roads become impassable, though wildlife is active and prices drop. Humpbacks pass in two seasons.

Honest expectations

Getting here is slow and expensive: the road from San José takes most of a day, and the last stretches are rough. Accommodation is mostly ecolodges at high prices with limited alternatives. Heat, humidity and insects are relentless. Malaria has been effectively eliminated in Costa Rica but dengue is present.

Nearby

Corcovado is at the centre; Drake Bay and Puerto Jiménez bracket it.