Ostional Wildlife Refuge
🇨🇷 Costa Rica
🐢 Pacific Ridley Arribada at OstionalOstional Wildlife Refuge protects one of the two most important olive ridley turtle nesting beaches on Earth. During peak season (September–November), up to 500,000 turtles emerge from the Pacific in a single arribada — an ancient synchronized mass-nesting event that occurs in only a handful of places worldwide.
9.958° N 85.653° W
Wildlife
⭐ Iconic Species
★ 
Pacific Ridley
Lepidochelys olivacea
★ 
Mantled Howler Monkey
Alouatta palliata
★ 
Black Spiny-tailed Iguana
Ctenosaura similis
★ 
White-nosed Coati
Nasua narica
📊 Most Spotted
Black Vulture
Coragyps atratus
Great Kiskadee
Pitangus sulphuratus
Green Iguana
Iguana iguana
Rufous-backed Wren
Campylorhynchus capistratus
Variegated Squirrel
Sciurus variegatoides
Great-tailed Grackle
Quiscalus mexicanus
Hoffmann's Woodpecker
Melanerpes hoffmannii
Black-headed Trogon
Trogon melanocephalus
Tropical Kingbird
Tyrannus melancholicus
Turkey Vulture
Cathartes aura
Brown Pelican
Pelecanus occidentalis
Spotted Sandpiper
Actitis macularius
⭐ Iconic Species
📊 Most Spotted
Variegated Squirrel
Sciurus variegatoides
Central American White-faced Capuchin
Cebus imitator
Common Raccoon
Procyon lotor
Northern Tamandua
Tamandua mexicana
Mexican Hairy Dwarf Porcupine
Sphiggurus mexicanus
Common tent-making Bat
Uroderma bilobatum
Gray Fox
Urocyon cinereoargenteus
White-tailed Deer
Odocoileus virginianus
Humpback Whale
Megaptera novaeangliae
Northern Ghost Bat
Diclidurus albus
Killer Whale
Orcinus orca
Greater Sac-winged Bat
Saccopteryx bilineata
📊 Most Spotted
Black Vulture
Coragyps atratus
Great Kiskadee
Pitangus sulphuratus
Rufous-backed Wren
Campylorhynchus capistratus
Great-tailed Grackle
Quiscalus mexicanus
Hoffmann's Woodpecker
Melanerpes hoffmannii
Black-headed Trogon
Trogon melanocephalus
Tropical Kingbird
Tyrannus melancholicus
Turkey Vulture
Cathartes aura
Brown Pelican
Pelecanus occidentalis
Spotted Sandpiper
Actitis macularius
Snowy Egret
Egretta thula
Orange-chinned Parakeet
Brotogeris jugularis
⭐ Iconic Species
📊 Most Spotted
Green Iguana
Iguana iguana
Rose-bellied Lizard
Sceloporus variabilis
Köhler’s Vine Snake
Oxybelis koehleri
Common House Gecko
Hemidactylus frenatus
American Crocodile
Crocodylus acutus
White-throated Gecko
Gonatodes albogularis
Central American Lyresnake
Trimorphodon quadruplex
Black-necked Centipede Snake
Tantilla armillata
Copper Anole
Anolis cupreus
Blackbelly Racerunner
Aspidoscelis deppii
Central American Boa
Boa imperator
Painted Wood Turtle
Rhinoclemmys pulcherrima
📊 Most Spotted
Giant Marine Toad
Rhinella horribilis
Mexican Smilisca
Smilisca baudinii
Milk Frog
Trachycephalus macrotis
Yellow Toad
Incilius luetkenii
Savage's Thin-toed Frog
Leptodactylus savagei
Dry Forest Toad
Incilius coccifer
Stauffer's Tree Frog
Scinax staufferi
Yellow Treefrog
Dendropsophus microcephalus
Sheep Frog
Hypopachus variolosus
Turbo White-lipped Frog
Leptodactylus poecilochilus
Masked Tree Frog
Smilisca phaeota
Boulenger's Snouted Tree Frog
Scinax boulengeri
Recent sightings in Ostional Wildlife Refuge
LIVEiNaturalistAnimal Events
1Olive Ridley Arribada
In one of the planet's greatest wildlife spectacles, tens to hundreds of thousands of Olive Ridley sea turtles storm ashore together over a handful of nights, hauling up the sand shoulder to shoulder to dig their nests. This synchronized mass nesting, known as an arribada, is the largest of its kind in the world.
2Green Turtle Nesting
Between the great ridley arribadas, green turtles and the immense leatherback — the largest sea turtle on Earth — come ashore alone under cover of darkness to nest on the same beach. Watching a solitary giant heave up the sand and carve out her nest is a quieter, more intimate turtle encounter.
3Coastal & Migratory Bird Season
During the northern winter the beach and river mouth fill with resident and migratory birds, from Brown Pelicans plunge-diving for fish to Snowy Egrets stalking the shallows. Overhead, Magnificent Frigatebirds ride the sea breeze on long angular wings, harrying other birds for their catch.
Sighting Calendar
Average chance of spotting the park's most-spotted species, month by month
- 1Olive Ridley Arribada
- 2Green Turtle Nesting
- 3Coastal & Migratory Bird Season
Sighting Zones
Warmer areas are where all species together are recorded most often.
Essentials
Climate
What visitors saw
During the four hours we saw an olive ridley as well as a green sea turtle (otherwise known as a black turtle in Costa Rica) which were trying to nest.
My group was incredibly lucky to see all 3 turtles spotted the first night of patrol and get to work on one within the first hour.
Wednesday night, we watched a video on sea turtles and egg harvesting at Ostional.
A few hours later, the numbers rose, and we found ourselves witnessing hundreds of Olive Ridley sea turtles crawling ashore was like nothing we’d ever seen.
Quick answers
What animals can you see in Ostional Wildlife Refuge?
The most likely sightings are Black Spiny-tailed Iguana (seen by about 80% of wildlife watchers), Mantled Howler Monkey (seen by about 80% of wildlife watchers), Black Vulture (seen by about 80% of wildlife watchers), Great Kiskadee (seen by about 70% of wildlife watchers), Green Iguana (seen by about 70% of wildlife watchers) — among 727 recorded vertebrate species, based on citizen-science data from GBIF.
When is the best time to visit Ostional Wildlife Refuge for wildlife?
May has the highest combined sighting rate for the park's top species in our month-by-month GBIF data. The full sighting calendar on this page shows each species' best months.
Can you see Pacific Ridley in Ostional Wildlife Refuge?
Yes — about 40% of wildlife watchers report a Pacific Ridley sighting in Ostional Wildlife Refuge, based on 27 verified sightings from GBIF citizen-science data.
Can you see Mantled Howler Monkey in Ostional Wildlife Refuge?
Yes — about 80% of wildlife watchers report a Mantled Howler Monkey sighting in Ostional Wildlife Refuge, based on 234 verified sightings from GBIF citizen-science data.
Can you see Black Spiny-tailed Iguana in Ostional Wildlife Refuge?
Yes — about 80% of wildlife watchers report a Black Spiny-tailed Iguana sighting in Ostional Wildlife Refuge, based on 233 verified sightings from GBIF citizen-science data.
Can you see White-nosed Coati in Ostional Wildlife Refuge?
Yes — about 50% of wildlife watchers report a White-nosed Coati sighting in Ostional Wildlife Refuge, based on 62 verified sightings from GBIF citizen-science data.
Where Wildlife Score
How good is this park for seeing wildlife?Biodiversity
GoodHow rich is the wildlife?
Sighting
Very goodHow likely to see animals?
Experience
GoodHow easy and pleasant is the visit?
