Costa Rica in December: Weather, Crowds, Costs & What to Do

Is December the dry season in Costa Rica?

On the Pacific side, yes. On the Caribbean side, no. The Instituto Meteorológico Nacional treats Costa Rica as two separate rainfall regimes rather than one country with one season, because the northwest to southeast run of the mountains splits the country into a Pacific slope and a Caribbean slope, and the IMN states that each slope presenta su propio régimen de precipitación y temperaturas.

For the Pacific slope the IMN wording is unambiguous. The dry season se extiende de diciembre hasta marzo, April is a transition month, and March is the driest and warmest. December is therefore the first month of the Pacific dry season, not the settled middle of it.

For the Caribbean slope the same IMN document says the regime no presenta una estación seca definida, because rainfall stays between 100 and 200 mm even in the least rainy months. The Caribbean runs two rainy peaks, one from November to January and a second from May to August, and the IMN names December as the wettest month of the Caribbean year. The driver is cold fronts arriving from the Northern Hemisphere, which the IMN says occur between November and May, with the greatest chance of affecting the country between November and March.

So the single most useful thing to know about December is that the country is not drying out evenly. An itinerary that runs Guanacaste and the central Pacific is working with the season. One that puts Tortuguero, Cahuita or Puerto Viejo into the same fortnight is working against it. The IMN also notes that Caribbean rain falls with greatest probability at night and in the morning, which is why a Caribbean December day can look ruined at 06:00 and be usable by noon.

Which part of Costa Rica dries out first in December?

The northwest. The IMN states that the onset of the Pacific dry season depende de la ubicación latitudinal, ya que comienza primero en el noroeste de la vertiente y de último en el sureste. Guanacaste and the Nicoya Peninsula turn dry earliest, the central Pacific follows, and the Osa Peninsula and the far south Pacific are last, sometimes not settling until the middle of the month.

That is the detail that decides whether the first week of December works for Corcovado, Drake Bay or the Golfo Dulce. The Pacific rainy season only ends in October, November is a transition month, and the IMN names September and October as the wettest months of the Pacific year. Early December in the far south sits closer to the tail of the wet season than to the start of the dry one, and the road and boat access down there is what suffers first.

The IMN divides the country into seven climate regions: Pacífico Norte, Pacífico Central, Pacífico Sur, Región Central, Zona Norte, Región Caribe Norte and Región Caribe Sur. Checking the forecast for the region you will actually stand in beats checking a national one, and it matters most around the continental divide. Arenal and Monteverde sit where the Caribbean regime spills across the mountains, so they can be wet on a day when Tamarindo, a three hour drive away, is cloudless.

One more IMN detail worth carrying: the Pacific rainy season has a mid-season dip, the veranillo, in July and August, when the trade winds strengthen. That is why some Costa Rica advice recommends July, and it is also why that advice does not transfer to December, when a completely different mechanism is at work.

Do you have to book Costa Rican national parks before you arrive?

For the busiest parks, yes, and in December the slots go first. The Sistema Nacional de Áreas de Conservación sells entry through its own Sistema de Compra y Reservación, SICORE, reached from www.sinac.go.cr and its online reservation page at sinac.go.cr/ES/resvlinea. The Instituto Costarricense de Turismo, announcing the switch for Manuel Antonio, wrote that a través del Sistema de Compra y Reservación (SICORE), los turistas podrán adquirir su boleto de ingreso.

Parque Nacional Manuel Antonio closes one day a week for maintenance, and that day is Tuesday. The ICT notice that moved the closure states the park would close on Tuesdays from 1 April, and SINAC's own park page gives the opening pattern as Wednesday to Monday, 7 a.m. to 3 p.m., with entry sold only through its online service. SINAC caps how many people it admits each day, which is the reason entry is sold by reservation rather than at the gate, so treat the cap as real and book before you fix the driving days around it.

Parque Nacional Volcán Poás is the tightest of the lot. The ICT notice on its return to visitor use states that sales run únicamente mediante el sitio www.sinac.go.cr, that admission windows run de las 7 a.m. hasta la 1 p.m., that visitors are organised into grupos de 50 visitantes, and that time at the crater viewpoint is capped at 20 minutos como máximo. Poás is an active volcano and its access rules change with its activity, so confirm the current slot pattern on the SINAC portal rather than assuming those numbers still hold.

Two things catch people out. A booking is tied to a date and a time window, so a change of plan means buying again rather than moving a reservation. And a sold-out day is genuinely sold out, because the cap is the point of the system. Re-check park rules on the SINAC portal within a week of travelling.

How much does it cost to enter a Costa Rican national park?

Between five and eighteen US dollars a day for a non-resident adult in most parks. The fees are set park by park in Decreto Ejecutivo 38295-MINAE, signed 15 January 2014, published in La Gaceta 82 of 30 April 2014 and in force from 1 July 2014. An eleven-year-old tariff invites the obvious question, so here is the answer: the Costa Rican legal information system carries the consolidated text as versión de la norma: 1 de 1 del 15/01/2014, meaning it has never been amended. The decree also repealed its predecessor, 34164-MINAE, so it is the operative instrument.

The decree fixes, for non-residents: Parque Nacional Chirripó at eighteen dollars per day; Manuel Antonio at sixteen dollars; Volcán Poás, Volcán Irazú, Volcán Arenal, Rincón de la Vieja, Tortuguero, Santa Rosa and Corcovado at fifteen dollars; Volcán Turrialba and Braulio Carrillo at twelve dollars; Marino Ballena, Marino Las Baulas and the Ostional wildlife refuge at twelve dollars; Monumento Nacional Guayabo and the Puerto Vargas and Playa Blanca sectors of Cahuita at five dollars. Isla del Coco, which is a ship journey rather than a drive, is fifty dollars a day. The Corcovado line is the one that surprises people: the decree gives a single day rate that also allows a visit to the Isla del Caño biological reserve on the same day.

Article 5 sets the non-resident child rate, ages six to twelve, at five dollars. Article 4 gives residents free access to SINAC protected areas on the second Wednesday of every month, which is worth knowing mainly because it makes those days busier. Article 3 states the tariffs are fixed in colones and in US dollars, converted at the Banco Central de Costa Rica selling rate current on the day the ticket is bought.

One warning about the arithmetic. The decree figure is not the figure you pay, because value added tax is applied at the online checkout, and the decree predates the current tax law. Take the payable total from the SINAC portal, not from the decree, and budget above the decree number. Entrance fees are also separate from guiding: Corcovado in particular is managed with guide requirements set by the conservation area, so confirm those with SINAC before you count on walking in alone.

What wildlife is genuinely in season in Costa Rica in December?

Humpback whales on the Pacific and leatherback turtles on the Guanacaste beaches, and both are governed by rules rather than luck.

On whales, SINAC's page for Parque Nacional Marino Ballena states that humpbacks appear in two seasons: those from the north from December to April, and those from the south from July to November, with resident dolphins present year round. December therefore sits at the start of the northern-hemisphere window, at the quieter end rather than the peak. Entry to Marino Ballena is twelve dollars for non-residents under the 2014 tariff decree.

Swimming with whales and dolphins is illegal in Costa Rica. Article 8 of the Reglamento para la Operación de Actividades Relacionadas con Cetáceos en Costa Rica, Decreto 32495, signed 20 January 2005 and published in La Gaceta 145 of 28 July 2005, reads: Es totalmente prohibido el nado o buceo, o cualquier otra actividad que implique entrar al agua con cetáceos en áreas confinadas o abiertas. The only exception is scientific work and professional underwater photography, and that needs a permit issued by SINAC inside protected areas or by INCOPESCA outside them. An operator offering you an in-water encounter is offering something the regulation forbids, which is a useful filter when you are choosing between boats.

The same regulation describes what a lawful trip looks like, which is the better test. Article 7 requires the operator to warn you beforehand that queda totalmente prohibido el nado o buceo con los cetáceos. Article 13 caps observation at 30 minutes or less, allows a maximum of two boats around any one group of cetaceans with any other boat holding 200 metres off, and prohibits approaching dolphins closer than 50 metres with the engine running, or 30 metres with it off. A boat that races another to a pod, or stays with it for an hour, is breaking the rules whether or not anyone gets into the water.

On turtles, Parque Nacional Marino Las Baulas de Guanacaste exists specifically to protect leatherback nesting, on Playa Grande, Playa Ventanas and Playa Langosta. December falls inside the nesting season, but this page does not print its exact start and end dates, because the SINAC pages that carry them would not load and the second-hand versions do not agree with each other. Night access to the nesting beaches is controlled by the park administration rather than open. Take the current season dates, the night-tour arrangements and the lighting rules from the park administration itself before you book around them. Park entry is twelve dollars for non-residents under the 2014 tariff decree.

What December is not is the Tortuguero green turtle season, and the Caribbean is also in its wettest month, so building a December trip around Caribbean turtle nesting is building it around the wrong calendar. A nesting season is a biological range, not a guarantee.

How busy is Costa Rica in December compared with the rest of the year?

December is the busiest month of the Costa Rican year, by a wide margin. The Instituto Costarricense de Turismo, using Dirección General de Migración y Extranjería records, counted 347,143 international tourist arrivals by all routes in December 2025, against 121,815 in September, the low point of the same year. The full year came to 2,943,991 arrivals. The same ICT table shows 2026 running ahead of 2025 through July, 2,001,660 arrivals against 1,882,024 for the same seven months, so there is nothing in the data to suggest a quieter December this time.

The shape of that year is the useful part. Arrivals run above 290,000 in January, February and March, fall through the middle of the year, bottom out in September, and then climb steeply: 145,663 in October, 247,387 in November, 347,143 in December. December is not simply busy, it is roughly two and a half times the September figure and higher than any month of the northern dry season that follows it.

International arrivals are only half of it. The last fortnight of December is also the domestic peak, because the Costa Rican school year has ended and the public holidays fall in it. That combination is what empties the coast road hotels, fills the national park reservation slots and pushes internal flights and car hire to their annual high. The practical effect is that the difference between 5 December and 27 December is far larger than the difference between two adjacent months anywhere else in the calendar.

If your dates are flexible, the first ten days of December give you the Pacific dry season starting to bite without the holiday load. If they are not, book park entry, internal flights and vehicles well ahead and accept that popular time slots will be gone.

What catches people out on a December trip to Costa Rica?

Four things, and all four are avoidable.

Treating one forecast as national. With seven IMN climate regions and two opposing rainfall regimes, a national outlook tells you very little. Look up the region, and expect the Caribbean to behave in the opposite direction to the Pacific for the whole month.

Assuming a cold front is a Caribbean-only problem. The IMN puts the cold front window at November to May, with the strongest likelihood from November to March, and those systems drive the Caribbean December maximum. They can also affect the mountain crossings between the two coasts, which is where a driving day is most exposed.

Arriving at a park gate without a reservation. Entry to the parks running SICORE is bought before you travel to the gate, tied to a date and a slot, and capped. In the last fortnight of December that cap is a hard limit, not a formality.

Budgeting from the decree. The 2014 tariff decree is the legal source for the fee, but the payable amount at checkout is higher once tax is added, and guiding, boat transfers and shuttle costs sit on top of it again.

Two re-check instructions before you go, both dated to 6 September 2026. Confirm park fees, opening days and available slots on the SINAC portal, since a 2014 decree can be amended and a volcano can change its own access rules. And confirm the entry requirements that apply to your passport with the Dirección General de Migración y Extranjería rather than with an airline booking screen.

At a glance

Fees as fixed by Decreto Ejecutivo 38295-MINAE. Value added tax is added at the SINAC online checkout, so the payable total is higher. Confirmed 6 September 2026.

Frequently asked questions

Is it raining in Costa Rica in December?

It depends entirely on which coast. The Instituto Meteorológico Nacional puts the Pacific dry season at December to March, so the Pacific is drying out. On the Caribbean slope the IMN names December as the wettest month of the year, driven by Northern Hemisphere cold fronts that the IMN dates to a November to May window. Caribbean rainfall does not drop below 100 to 200 mm even in that slope's least rainy months.

Which part of Costa Rica is driest in early December?

The northwest. The IMN states the Pacific dry season begins first in the northwest of the slope and last in the southeast, so Guanacaste and Nicoya are reliably dry before the Osa Peninsula and the south Pacific are. If your dates are in the first week of December, the far south is the riskiest choice.

Do you need to book Costa Rica national park tickets in advance?

For the parks on the SICORE system, yes. SINAC sells entry through www.sinac.go.cr and its online reservation page, tied to a specific date and time window, with a daily cap. Manuel Antonio closes on Tuesdays. Volcán Poás admits visitors in timed windows and, per the ICT notice, in groups of 50 with 20 minutes at the crater viewpoint. Check the portal within a week of travelling.

How much is entry to Manuel Antonio National Park?

Decreto Ejecutivo 38295-MINAE sets the non-resident adult rate at sixteen US dollars, with non-resident children aged six to twelve at five dollars. Value added tax is added at the SINAC online checkout, so the amount you pay is higher than the decree figure. Take the payable total from the portal.

Can you see whales in Costa Rica in December?

Yes, at the start of one of the two seasons. SINAC's Marino Ballena page gives the northern humpback season as December to April and the southern one as July to November, with resident dolphins year round. Note that article 8 of Decreto 32495, the cetacean activities regulation published in La Gaceta 145 of 28 July 2005, states that swimming or diving with cetaceans, or any activity that involves entering the water with them, is totally prohibited outside permitted scientific and professional underwater filming work. Observation is capped at 30 minutes with a maximum of two boats around any one group. An in-water encounter is not a legal offer.

Is December the most crowded month in Costa Rica?

Yes. ICT figures compiled from Migración records record 347,143 international arrivals by all routes in December 2025, the highest month of a year that totalled 2,943,991, against 121,815 in September. The last two weeks are also the domestic holiday peak, so park slots, internal flights and vehicles are at their tightest then.

When is leatherback turtle nesting season in Guanacaste?

Parque Nacional Marino Las Baulas de Guanacaste protects leatherback nesting on Playa Grande, Playa Ventanas and Playa Langosta, and December falls inside the season. This page does not give the season's exact start and end dates: the SINAC pages carrying them would not load and the second-hand versions disagree. Night access to the nesting beaches is controlled by the park administration, so get the dates, the night-tour arrangements and the lighting rules from the park directly. Entry is twelve US dollars for non-residents under Decreto 38295-MINAE.