Costa Rica.

Costa Rica fits roughly the size of West Virginia but contains an estimated 5% of the world's biodiversity, sloths and toucans in the lowlands, quetzals in the cloud forests, humpback whales off both coasts, 900+ bird species, four species of nesting sea turtles, and the highest density of biodiversity on Earth on the Osa Peninsula. The country abolished its army in 1948 and reinvested in education, healthcare, and conservation. Today roughly 25% of its territory is protected as national parks and reserves. The result: a country built around nature in a way that makes wildlife genuinely accessible, three-toed sloths in Manuel Antonio, scarlet macaws on the Osa, humpbacks breaching off Marino Ballena, all in one two-week trip.

Pick your angle before your dates. The Costa Ricas most travelers come for each have their own seasonal logic.

1) Pacific North (Guanacaste). Tamarindo, Nosara, Santa Teresa, Papagayo. Driest part of the country, almost desert-like in late dry season. Surf year-round, peak December–April. Liberia airport.

2) Pacific Central. Manuel Antonio, Quepos, Jacó. Beach-meets-rainforest, sloths and capuchins on the trails. Wettest October–November.

3) Pacific South (Osa Peninsula, Corcovado, Drake Bay). The wildest, most biodiverse corner. Wet year-round but still seasonal. National Geographic called Corcovado the most biologically intense place on Earth. Ranger-guided hikes required.

4) Caribbean coast. Tortuguero (boat-only, jungle channels, turtle nesting), Puerto Viejo, Cahuita. Wetter on average but with a reverse calendar, September–October often the driest weeks. Afro-Caribbean culture, reggae, jerk chicken.

5) Highlands and volcanoes. Arenal/La Fortuna (volcano + hot springs), Monteverde (cloud forest, quetzals, ziplines), Rincón de la Vieja (volcanic mud baths), San Gerardo de Dota (best quetzal viewing). Cool 18–22°C year-round.

You cannot do it all in 10 days. A reasonable first trip is three regions, Arenal + Monteverde + one Pacific beach. Add Tortuguero or Osa with 12+ days.

Costa Rica's macro calendar has two seasons and one major regional inversion that catches first-timers off guard.

Dry season (December–April). Pacific skies blue, trails dusty, roads passable, wildlife concentrated around remaining water (easier to spot). Both coasts run 27–32°C, highlands cool to 18–22°C. Downsides: peak tourist season and Semana Santa (Easter week) is the biggest peak. Christmas–New Year (Dec 22 – Jan 5) and Semana Santa see prices 2–2.5x normal; rooms in Manuel Antonio, Tamarindo, and La Fortuna sell out 2–3 months ahead.

Green season (May–November). Rain arrives in May, builds through August, peaks in September and October, the wettest two months on the Pacific. Rarely all-day rain: mornings clear and warm, thunderstorms roll in late afternoon. Roads to remote lodges (Tortuguero, Osa) can flood; some smaller eco-lodges close September–October. Wins: prices drop 30–50%, country electric green, waterfalls at peak flow, and wildlife calendar at its peak, turtles nesting, whales calving, quetzals breeding.

Veranillo de San Juan (mid-to-late July). A brief 2–3 week dry break inside green season. Pacific gets reliable sunny days, prices stay low, wildlife peaks. One of the year's best value windows, weather not guaranteed but historically reliable.

The Caribbean inversion. The Caribbean coast (Tortuguero, Puerto Viejo, Cahuita) often gets its driest weeks in September and October, exactly when the Pacific is wettest. Tortuguero's green turtle nesting peaks August–September, lining up with the Caribbean's relative dry window. If your priority is turtles or Afro-Caribbean culture, September–October are arguably the best months, at green-season rates.

Optimal windows.

• Late December to mid-February. Prime dry-season weather, post-Christmas prices, whale season, pre-Semana-Santa. Best overall for first-timers.
• Mid-July (the veranillo). Green-season prices, turtle nesting building, fewer crowds. Best value window.
• September–October. Skip Pacific, go Caribbean. Tortuguero turtles peaking, Puerto Viejo sunniest, prices at year-low.
• Late November. Rains tapering, dry starting, prices moderate. Excellent shoulder.

Two-week samples. Jan–Feb: San José 1 → Arenal 3 → Monteverde 2 → Manuel Antonio 3 → Drake Bay 3 → San José 1. July: Arenal 3 → Monteverde 2 → Nosara 4 → Manuel Antonio 3 → San José 1. Sep–Oct: San José 1 → Tortuguero 3 → Puerto Viejo 4 → Arenal 3 → Monteverde 2 → San José 1.

Costa Rica's wildlife is the headline reason most travelers come, and almost every species has a seasonal window worth timing around.

Sea turtles. Tortuguero (Caribbean) is the largest nesting site for endangered green turtles in the Western Hemisphere. Green turtles nest July through mid-October, peak August–September; leatherbacks (up to 700 kg) nest February–April. Guided night tours $25–35; no flash, red lights only. Ostional (Pacific Nicoya) hosts the arribada, mass synchronized olive ridley nesting. Arribadas peak July–December, August–October most reliable. Playa Grande / Las Baulas sees leatherbacks October–February. Book through your lodge 2–3 days ahead.

Whales. Marino Ballena (south Pacific) sees humpbacks twice, southern pod July–November (calves visible) and northern pod December–March. Boat tours from Uvita $80–120. The whale-tail-shaped sandbar at low tide is iconic.

Quetzals. The resplendent quetzal is among the most coveted birds in the Americas. Best viewing March–July during nesting. San Gerardo de Dota is statistically the best spot; Monteverde runs guided dawn walks January–May. Book a 5 AM tour.

Sloths and macaws. Sloths year-round at Manuel Antonio, Cahuita, La Selva, and the Sloth Sanctuary. Scarlet macaws year-round on the Osa Peninsula and Carara National Park.

Surf. Year-round. Pacific north (Tamarindo, Witch's Rock) best December–April; Pacific south (Pavones, second-longest left in the world) best May–October; Santa Teresa and Nosara year-round.

Adventure. Pacuare River (class III–IV whitewater), peak flow May–November. Ziplining invented in Monteverde. Arenal hot springs (Tabacón, Eco Termales) volcano-fed, year-round. Hanging bridges in Arenal and Monteverde. Night tours in Cahuita, Tortuguero, Monteverde.

Closures. Manuel Antonio is closed Tuesdays year-round with a daily visitor cap, book 2–7 days ahead at sinac.go.cr. Corcovado requires a licensed ranger guide (no DIY); book through Drake Bay or Puerto Jiménez operators 1–2 weeks ahead in dry season.

Costa Rica is one of the easier countries in Latin America for Western travelers, safest in Central America, English widely spoken in tourism zones, USD accepted everywhere, but a few realities catch first-timers.

Visa. Most Western passports (US, Canada, UK, EU, Australia, NZ, Japan) receive up to 90 days visa-free on arrival. Onward or return ticket required (rarely checked). Tourist exit tax of $29 included in airline tickets.

Currency. Costa Rican colón (CRC) is official, but USD is accepted virtually everywhere in the tourism economy. Rough rate in 2026: ~520 CRC = 1 USD. Cards accepted at hotels, restaurants, supermarkets, most tour operators. Cash useful in rural areas, small sodas, and for tips. ATMs everywhere in cities; less common on the Caribbean and Osa.

The rental car insurance trap. The single most-mentioned gotcha in Costa Rica. Rates look cheap online ($15–30/day) but Costa Rica requires mandatory third-party liability insurance (SLI/INS) that most foreign credit-card collision coverage does not satisfy. Companies layer it on at the counter, typically $15–25/day, pushing real costs to $40–80/day economy and $70–130/day 4WD. Always quote all-in pricing before booking. Operators that disclose all-in: Adobe, Vamos, Wild Rider. 4WD recommended for Nicoya, Osa, Monteverde back roads, and any rainy-season travel.

Driving and flights. Main routes paved and good; secondary routes often dirt and slow. GPS times are wildly optimistic, add 30–50%. Don't drive at night outside cities. Sansa and Skyway run small-plane domestic flights at $80–150 one-way, worth it for Drake Bay and Tortuguero, skippable for Manuel Antonio.

Costs. Costa Rica is mid-range Latin America, pricier than Guatemala/Nicaragua, cheaper than the US Caribbean.

• Backpacker / hostel + sodas: $50–80/day. Hostel dorm $20–35, casado (set lunch) $5–10.
• Mid-range / private guesthouse: $100–180/day. Hotel $80–150, restaurant $15–30, rental car shared.
• Comfort / 4-star + tours: $250–400/day. Hotel $180–300, dining $40–70, tours $60–120.
• Eco-lodge / luxury: $300–800+/day. Lapa Rios, Pacuare Lodge, El Silencio, Nayara Tented Camp.

Two adults, 14 days, mid-range, San José–Arenal–Monteverde–Manuel Antonio loop: budget $3,000–4,500 on the ground plus international flights ($350–600 from US East Coast).

Tipping. 10% servicio is usually included on restaurant bills. Round up taxis, $5–10/day housekeeping, $20–40/group/day for guides.

Health and safety. Tap water safe in San José and most populated areas; bottled in remote Caribbean and Osa. No yellow fever required unless arriving from a yellow-fever country. Dengue and Zika real year-round, worse in green season and on the Caribbean, DEET, long sleeves dawn/dusk. Malaria essentially absent. No army since 1948; the country is generally safe. Petty theft is the main risk, never leave anything visible in a parked rental car. Riptides are the deadliest hazard at Pacific beaches; heed flags. Etiquette: Tico/Tica = Costa Rican; "Pura vida" = pure life, used as hello, goodbye, and the national philosophy.