The high (summer) season runs from November to April, and though it's also classed as the 'dry' season it doesn't necessarily mean there will be no rain - but there should be less of it! Prices are higher during this time. The 'green' season (from May to November) can still be a good time to visit, especially the early months when days can start off with sunshine then turn rainy in the afternoon/evening. More careful planning is required then, though, as some roads become impassable (even in a 4x4).
Bird-watchers will be happy year-round: flocks migrate to Costa Rica between September and November, though those in search of the resplendent quetzal will be more sucessful between November and May. For turtle enthusiasts the leatherback can be seen nesting in Tortuguero (on the Caribbean coast) from mid-February to mid-April, or on the Pacific coast between September and March. Green turtles nest on the Caribbean coast during August and September.
There are public holidays throughout the year, normally around one per month. The main celebration is Semana Santa (Holy Week or Easter) - hotels are busier during this time so availability may be scarce.
NB, please do not rely solely on this information for your travel planning.
COSTA RICA:BY AIR
From Europe: carriers include British Airways and Iberia (San José) or TUI (Liberia).
From the USA: try Delta, American Airlines, United Airlines, US Airways, Northwest, Continental and Spirit Air.
BY BOAT: There's a regular boat service connecting Los Chiles with San Carlos, on the southeast corner of Lake Nicaragua.
INTERNAL FLIGHTS: carriers include Nature Air and Sansa.
BY CAR: We don't advise you to hire a car - roads to most rural areas are poor with no signage and rivers can rise dramatically. If you really want the freedom of your own vehicle see our car rental recommendations.
TRANSFERS: Most hotels will arrange transfers to nearby hotels, or to and from San José and Liberia if required.
BY BOAT: There are ferries connecting the central Pacific coast with Paquera on the southern tip of the Nicoya Península, and services connecting Puntarenas with Playa Naranjo and Vaquero. On the Osa Peninsula's Golfo Dulce, there's a daily passenger ferry between Golfito and Puerto Jiménez, and a weekday water taxi to Playa Zancudo. There's also a water taxi between Bahía Drake and Sierpe. On the Caribbean coast, a bus-and-boat service runs several times daily from Cariari to Tortuguero. Canal boats travel from Moín to Tortuguero, although no regular service exists. A daily water taxi connects Puerto Viejo de Sarapiquí with Trinidad, Nicaragua, on the Río San Juan.
HEALTH & SAFETY
Some vaccines may be required for travel to Costa Rica - check with your doctor. Malaria and Dengue Fever are present in some areas of the country, so seek medical advice about whether you need to take anti-malarials at least a month before you travel, and always wear mosquito repellent (preferably one containing DEET).
Tap water is generally safe to drink in Costa Rica, but stick to bottled water in remote areas. Always wear closed, heavy-soled footwear in jungle areas to protect against snake bites (Costa Rica is home to several venemous species).