White-water rafting is the ultimate combination of beauty and thrill—an ideal way to savor Costa Rica’s natural splendor and exotic wildlife. Because the land is so steep, streams pass through hugely varied landscapes within relatively short distances. Rainforest lines the riverbanks.
You’ll tumble through a tropical Fantasia of feathery bamboo, ferns, and palms, a roller-coaster ride amid glistening jungle. Everything is as silent as a graveyard, except for the chattering of monkeys and birds.
Rafters are required to wear helmets and life jackets, which are provided by tour operators. Generally, all you need to bring is a swimsuit, a T-shirt, and tennis shoes or sneakers. Sunscreen is a good idea, as you are not only in the open all day, but also exposed to reflections off the water.
You’ll also need an extra set of clothing, and perhaps a sweater or jacket, as you can easily get chilled if a breeze kicks up when you’re wet. And you will get wet. Most operators provide a special waterproof bag for cameras. One-day trips start at about $75.
Generally, May–June and September–October are the best times for high water. Rivers are rated from Class I to VI in degree of difficulty, with V considered for true experts only.
The Río Chirripó (Class III–IV) runs down the slopes of the southwest Pacific and is recommended for two- to four-day trips. The river, which tumbles from its source on Mount Chirripó, has been compared to California’s Tuolomne River and Idaho’s Middle Fork of the Salmon, with massive volumes of water and giant waves.
The Río Corobicí (Class II) provides more of a float trip and makes an ideal half-day trip for families, with superb wildlife-viewing and calm waters the whole way. The river flows westward through Guanacaste into the Gulf of Nicoya. It is runnable year-round.
The high-volume Río General is famous for its dramatic gorges, challenging rapids, and big waves ideal for surfing.
Río Naranjo and Río Savegre, in the mountains above Manuel Antonio on the Central Pacific coast, are real corkers in high water, with swirling Class IV action. However, they’re inconsistent, with dramatic changes in water level. The upper sections run through rainforest; lower down, they slow through ranch land before winding through Manuel Antonio National Park  and exiting into the Pacific.
For an in-depth immersion in nature, the Río Pacuaré (Class III–IV) is the best choice as it slices through virgin rainforest, plunging through mountain gorges to spill onto the Caribbean plains near Siquirres . Toucans, monkeys, and other animals galore make this journey unforgettable. Overhead loom cliffs from which waterfalls drop right into the river. Black tongues of lava stick out into the river, creating large, technically demanding rapids and making great lunch beaches. And steep drops produce big waves. The best months are June and October.
The Río Reventazón (Class II–V) tumbles out of Lake Angostura and cascades to the Caribbean lowlands in an exciting series of rapids. Beginners can savor Class II and III rapids on the “mid-section,” the most popular run for one-day trips. The Guayabo  section offers Class V runs. Constant rainfall allows operators to offer trips year-round; June and July are the best months.
The Río Sarapiquí (Class III) runs along the eastern flank of the Cordillera Central and drops to the Caribbean lowlands. It is noted for its crystal-clear water, variable terrain, and exciting rapids. Trips are offered May–December.
In Costa Rica, I recommend Costa Rica Expeditions (tel. 506/2257-0766, www.costaricaexpeditions.com ), which offers one-day and multiday trips on most major rivers. The other preeminent operator is Ríos Tropicales (tel. 506/233-6455, www.riostropicales.com ), which runs the Corobicí, Sarapiquí, Reventazón, General, and Pacuaré rivers. Numerous smaller companies also offer white-water trips.