Two Coasts and a Cloud Forest
A country you can cross in a morning, arranged so you never backtrack: Caribbean turtles and Afro-Caribbean cooking, the Arenal volcano, Monteverde’s cloud forest, and a Pacific finish on the Osa peninsula where the biology gets serious.
San José, briefly
Land, collect the rental car or confirm the shuttles, and give the capital an afternoon: the Pre-Columbian Gold Museum and the Jade Museum are both excellent and both take ninety minutes. Nobody comes to Costa Rica for San José, and that is fine.
To Tortuguero
Northeast to the Caribbean lowlands, then the last leg by boat — there is no road in. The village sits on a sandbar between canals and ocean, and the whole park is navigated by water.
Canals at dawn
The early boat is the wildlife boat: caimans, howler monkeys, three species of kingfisher, and — if you are lucky and the guide is good — a sloth doing almost nothing very slowly. In green turtle nesting season (roughly July to October) the night beach tours run under strict quota with a licensed guide.
South to Puerto Viejo
Back out by boat and down the Caribbean coast to Puerto Viejo de Talamanca — reggae, rice and beans cooked in coconut milk, and a Bribri and Afro-Caribbean culture that is not much like the rest of the country.
Cahuita and the reef
The national park at Cahuita is a coastal walk with a fringing reef offshore and a coral system under long-term stress from sediment and warming. Snorkel with a guide from the village end. Afternoon: the beaches south toward Manzanillo.
Across to Arenal
A long transit day across the country to La Fortuna, under the near-perfect cone of Arenal — which erupted continuously from 1968 until it went quiet in 2010, and now steams politely for the cameras.
Bridges, lava fields and hot water
The hanging-bridge trails put you in the canopy where the birds actually are; the 1968 lava-field trail puts you on the old flow with the volcano above. Finish in a thermal river — the free public stretch at El Choyín is as good as the resort versions.
Jeep–boat–jeep to Monteverde
The classic crossing: vehicle to Lake Arenal, boat across, vehicle up the other side. Three hours instead of a five-hour road loop, and the lake view of the volcano is the best one there is.
Inside the cloud
The Monteverde reserve exists because Quaker settlers bought the watershed in the 1950s and refused to log it. Go at opening in the mist, walk the continental divide trail, and treat the resplendent quetzal as a bonus rather than a plan.
South to the Osa
The longest drive of the trip, down the Pacific side to Drake Bay or Puerto Jiménez. Break it at Manuel Antonio if you want the postcard beach, but know that the park is small and heavily visited and the Osa is the reason you came.
Corcovado
National Geographic once called this the most biologically intense place on earth and the description has stuck because it is roughly true. Entry requires an advance permit and a certified guide. Tapirs, four monkey species, scarlet macaws in numbers, and a realistic chance of tracks you would rather see than the animal.
Out
Fly from Puerto Jiménez or Drake Bay back to San José in a small plane over the peninsula — twenty minutes that show you exactly how much forest is down there — and connect home.
Good to know
Corcovado requires a permit and a certified guide, booked in advance; day entry without both is not possible. Tortuguero’s turtle tours are quotaed and guided in season.
The Caribbean side has its own rhythm of rain — September and October, the wettest months on the Pacific, are often the best on the Caribbean.
Roads are the real constraint. A 4x4 matters on the Osa and around Monteverde; elsewhere a normal car is fine, and shuttles cost little more than fuel for two people.
Shorter or longer?
Arenal, Monteverde and Manuel Antonio — the classic loop, with no Caribbean or Osa legs.
Add four days on the northern Pacific for Santa Teresa, Montezuma and the Curú reserve.
Cross north from Liberia to Granada and Ometepe for a week before returning.