Costa Rica Humpback Whale Season: Why There Are Two

So when is humpback whale season in Costa Rica? The short answer is that there are two. Southern whales visit roughly from July to November, and northern whales roughly from December to March. Sources draw the edges a little differently, and no single day is ever guaranteed.

I love this detail. A coast that welcomes whales from both ends of the planet, one family after the other, like guests who share a house but never the same week. It is also a good reason to be honest about what a long season means, and what it does not. A long season is not an invitation to get in the water.

Two populations, two seasons

Humpbacks do not live in Costa Rica. They visit. Whales that feed in the Southern Hemisphere reach the Pacific coast in the middle of the year, and whales that feed in the north arrive after the turn of the year. Travel and park sources describe the southern group arriving from about July and staying into October or November. The northern group, travelling down from Alaska and the west coast of North America, arrives from December until about March.

The International Whaling Commission (IWC) Whale Watching Handbook, which is more careful than most tourism pages, describes the windows in the same way. Other websites give slightly different edges, and one park source gives the northern whales a shorter, smaller visit. I do not know which edge is “right”, and I do not think anyone does, because the ocean does not read calendars. Where sources disagree, I trust the broad picture and ask a local guide in the week I travel.

Why do humpback whales come to Costa Rica?

Not to eat. Humpbacks feed in cold, rich water far away, then travel to warm tropical water to mate and give birth. That is why many of the whales seen from boats in Costa Rica are mothers with young calves. It is also why the rules I explain below matter so much. A newborn calf needs to rest, to breathe and to drink milk, and a mother needs calm space to let it do all three.

One national park on the south Pacific coast, Marino Ballena near Uvita, is even named after the whales. Some travel pages explain the richness of the area with a thermal dome and plankton. I found this only in tourism sources and could not confirm it as science, so I will not present it as fact. If you are curious about the animal itself, our humpback whale page in the Ocean Atlas is a good place to start.

Where the watching happens

Whale watching boats leave from several places on the Pacific side. The names that come up again and again in guides are Uvita and the Bahía Ballena area, and the Osa Peninsula and Golfo Dulce further south. A good boat day there is more than a quick look at a fin. A guide who knows the coast explains where the animals may be travelling, what a surface behaviour might mean and why a mother with a calf needs room. The birds, the green coastline and the colour of the water are part of the day too.

If you are choosing between places, ask which season you will travel in and which population you could meet. It changes the story of the day, not the rules. Our guide on why ethical whale encounters often mean fewer sightings may help you set gentle expectations.

A long season is not a swim season

Costa Rica regulates whale and dolphin activities under Executive Decree 32495, the regulation for activities related to cetaceans, published in 2005. As the IWC handbook summarises it, feeding, swimming with and diving with dolphins and whales is strictly prohibited in the country’s coastal waters. The decree also asks for a register of operators, so that boats running these trips are known to the authorities.

So for us the answer is simple. A tourist swim with whales or dolphins in Costa Rica is off the table. A warm bay, a friendly advert or a boat that offers “a quick dip” does not change that. Rules can change, so check the current rule before you travel. But I would also quietly ask why anyone would offer something the national rules do not allow.

What a good boat watch looks like

The IWC summary of the Costa Rican rules gives numbers you can use as a small checklist: a minimum approach distance of 100 m for whales and 50 m for dolphins, an observation time of no more than 30 minutes, and no more than two boats with the same group at one time. Boats should approach slowly, from behind and at an angle of about 45 degrees. In simple words: never head on, never cutting in front, never in a hurry.

The same IWC page notes that enforcement is limited by resources. That is the honest part of this story. A rule on paper is only as strong as the boat you are sitting in, so the choice of operator is where the ethics really happen. I could not find a separate mother and calf rule in the sources I used, so I will not quote one. Still, I would expect any good guide to give a mother with a calf extra room, and to leave sooner, not later. Wildlife encounters are unpredictable. Whale watching should always follow local regulations and experienced professional guidance.

Before you book, ask how the boat behaves if the animals change direction, how long it stays and whether the trip is cancelled in poor conditions. On the day, keep your voice low, stay seated when asked and accept that the whales may simply leave. A small roll-top dry bag keeps a phone and a spare layer dry on a splashy boat, so your hands are free and your eyes stay on the water. On a long morning on deck, a refillable bottle from a tropical travel kit list is one less thing to buy in plastic.

The honest cost of getting there

Whale trips are not light. Most of us fly a long way to meet a migrating animal, and that has a footprint. I do not think the answer is never to go. I think it is to go slowly, stay longer, choose small boats and operators who follow the rules, and be glad of a good day without needing a perfect one. That is the thinking behind our green flags and red flags for whale encounters.

A season is an invitation to be present, not a promise of closeness. If this made you curious about travelling this way, you can explore our retreats.

Questions people ask

Wildlife encounters are never guaranteed and never forced. Ocean Calling works only with vetted, ethical local operators, and every animal is free to approach, or not, entirely on its own terms.