A view of the Golfo Dulce off the coast of Costa Rica.

Cruising Golfo Dulce

Many travelers are drawn to Costa Rica to explore its Arenal volcano, to lounge on the beaches along the Guanacaste peninsula and to hit the zip lines all over this jungly Central American nation. But fewer outsiders have discovered the quirky-shaped Osa Peninsula, the country's most eco-rich environment. It sits on the south Pacific coast, hard against the Panama border, where there are few roads and fewer towns.

If you were ever to design a gulf, you could do no better than the deep, well-protected Golfo Dulce, bordering the Osa Peninsula's eastern shore. In English, the name translates as \"sweet gulf,\" and that's probably how it appeared to Sir Francis Drake and other early sailors and explorers. But in Spanish, fresh water is called \"sweet water,\" and the gulf's name actually refers to the rain-forest runoff that accounts for the low salinity of the surface water. The gulf is lined with fine and mostly empty beaches; inland, dense nature reserves are home to monkeys, birds and endangered cats. As a vital part of the ecosystem, mangrove swamps spread out from the deltas of tributary rivers.