Laguna de Castillos

A protected coastal lagoon in Rocha department, Laguna de Castillos harbors a unique yatay palm forest, rich birdlife, and one of Uruguay's rare giant otter populations.

Laguna de Castillos is a vast coastal lagoon in Rocha department in eastern Uruguay. It stretches across several thousand hectares between the town of Castillos and the Atlantic Ocean, separated from the sea by a sand barrier. This freshwater body supports remarkable biodiversity and represents one of the few natural habitats of the giant river otter in Uruguay. The site is also renowned for the yatay palm forest lining its shores.

What you'll see

The lagoon offers a landscape of open wetlands, populated with aquatic birds—herons, roseate spoonbills, ibises, ducks and jacanas. Along its banks grows the forest of Butia odorata (yatay palm), a protected endemic species. The giant otter (Pteronura brasiliensis), a vulnerable species, has been reintroduced and is regularly observed here. The sand barrier separating the lagoon from the Atlantic creates a striking contrast between freshwater and open sea.

History and context

The Rocha region has long been preserved from intensive development, allowing its lagoon ecosystems to remain intact. Laguna de Castillos is part of Uruguay's coastal lagoon system, classified as a protected area under Uruguay's National System of Protected Areas (SNAP). The associated palm forest is considered one of the largest surviving yatay palm forests in the world.

Highlights of a visit

The yatay palm grove

Thousands of Butia odorata palms line the lagoon's shores. This forest is a remnant of an ecosystem once far more extensive throughout the Río de la Plata region. Walking through the palms, especially in late afternoon, is a powerful visual experience.

Birdwatching

The lagoon is a premier birdwatching site in eastern Uruguay. Roseate spoonbills, cocoi herons, bare-faced ibises and numerous duck species frequent the shores. Early mornings offer the best viewing opportunities.

The giant otter

The presence of the giant otter makes this one of the few places in Uruguay where you can observe this semi-aquatic mammal. Boat outings with a local guide significantly increase your chances of seeing one.

Photography tips

Golden light in early morning and evening highlights the silhouettes of yatay palms against the sky. For birds, a telephoto lens is essential. From a boat, you get sweeping angles across the water that reveal the density of the palm forest. Avoid midday sun, which flattens contrast.

Location and access

Laguna de Castillos is located immediately near the town of Castillos, the capital of Rocha department. Route 9 (Ruta 9) connects Castillos to Montevideo to the west and to Chuy (Brazilian border) to the east. Access to the lagoon's shores is via dirt roads from town. Local guides offer boat trips to explore the lagoon and palm forest. Terrain can be muddy after rain; a high-clearance vehicle is recommended for some access points.

Nearby

Laguna de Rocha — another protected coastal lagoon in the department, to the west, with similar biodiversity.
Cabo Polonio — isolated Atlantic village, accessible only by 4x4, known for its sea lion colony and dunes.
Santa Teresa National Park — colonial fortress and wild beaches north of Rocha department.
Aguas Dulces — quiet coastal village on the Atlantic coast, east of Castillos.

Frequently asked questions

Southern spring (September-November) and autumn (March-May) offer the best conditions: mild temperatures, migratory birds present and dense vegetation. Summer (December-February) is warm and busy; winter remains pleasant but some birds are absent.

Sightings are not guaranteed. An early morning boat trip with a local guide significantly increases your chances. The giant otter is active at dawn and in late afternoon.

A guide is not required for walking along the shores on foot, but is strongly recommended for boat trips and wildlife observation. Local operators based in Castillos offer these excursions.

Castillos sits on Ruta 9, the main axis of eastern Uruguay's coast. You can easily combine the lagoon with Cabo Polonio (about 30 km away) and Laguna de Rocha in a two to three-day circuit through the department.

Access to the lagoon's shores is free. Organized boat trips with local guides are paid; rates vary by operator and excursion duration.