Costa Rica is home to roughly 5% of the world's biodiversity, and that statistic does a lot of work in travel brochures. What it does not tell you is the practical part: which animals you can realistically expect to see, where, and at what time of day.
Wildlife keeps its own schedule. Here is what that means for planning.
Sloths: early morning or mid-afternoon
Sloths are the animal most visitors come hoping to see, and the Arenal region is where you are most likely to.
Dedicated sloth tours run at 6:00 am or 2:00 pm and take about 2.5 hours, travelling the roads around the volcano with a bilingual naturalist guide who spots both two-toed and three-toed sloths. Those departure times are not arbitrary — and a guide who knows individual trees is the difference between seeing a sloth and seeing a shape in a canopy.
There is also a longer afternoon option that pairs sloth-spotting with an evening in the hot springs, departing 1:30 pm.
River wildlife: mid-morning or early afternoon
The Peñas Blancas River float near Arenal is the most relaxed wildlife outing available: a naturalist guide does the rowing while you watch for monkeys, sloths, reptiles and tropical birds. It departs at 8:25 am or 1:25 pm and takes about 3.5 hours.
Moving quietly on water rather than walking through forest is a genuine advantage — you disturb far less, and animals along the banks are habituated to boats.
Birds: the full-day option
For serious birdwatching, the Caño Negro Wildlife Refuge boat safari is the most substantial wildlife experience on offer — 8 hours from 7:00 am, reaching one of the best destinations in Costa Rica for spotting a wide variety of animals, especially birds. The drive passes local plantations of cassava, papaya, pineapple and sugar cane.
This is a full day, and it is aimed at people for whom the wildlife is the point rather than one activity among several.
Frogs: after dark
The rainforest at night is a different place, and this is the one thing on this list you cannot see during the day.
Arenal's night walk visits the region's only wild frog sanctuary — flat trails and natural spring-fed ponds in a private reserve connecting to the volcano's rainforest, with up to 28 species of frogs plus other nocturnal wildlife. It starts at 6:00 pm.
Monteverde has its own version, starting slightly earlier at 5:30 pm, where the cloud forest takes on a completely different character after sunset.
Cloud forest species: the guided walk
Monteverde's wildlife is harder to see and more rewarding when you do. On a guided walk through the well-maintained trails of the Santa Elena Reserve, an expert guide can find howler monkeys, coatimundis, and a variety of birds including the elusive resplendent quetzal.
Walks run from 6:30 am through 12:30 pm. The earliest departure is the better bet for birds, which are most active shortly after dawn.
Sea turtles: Tortuguero, seasonally
Tortuguero is famous for sea-turtle nesting along its canals. The nesting is seasonal, and if it is the reason for your trip, confirm the timing before building an itinerary around it rather than relying on a date you read somewhere.
Planning around it
Most wildlife activity concentrates early and late — dawn departures for birds and sloths, evening walks for frogs and nocturnal species. Midday is when animals are least active, which conveniently leaves the middle of the day for things that do not care what time it is: ziplines, hot springs, waterfalls, canopy bridges and farm tours.
Plan wildlife around the edges and everything else in between, and you will fit considerably more into the same trip.