Geography and context
Puerto Deseado is a coastal city in Santa Cruz Province, on the northern bank of the Ría Deseado estuary, 221 km from Caleta Olivia. The city had 16,812 inhabitants in the 2022 census.
The Ría Deseado is the estuary where the Río Deseado meets the Atlantic Ocean. According to Wikipedia, it extends approximately 50–53 km inland with a mouth about 7 km wide between Punta Guanaco and Península Foca. The ría represents an unusual geological case: an ancient river channel that was invaded by ocean waters millennia ago, creating its distinctive estuary configuration and rich transitional ecosystem.
What you’ll see
The Ría Deseado is one of the most biodiverse estuaries in southern Patagonia. Tidal currents concentrate zooplankton and microorganisms, supporting a visible and complex food chain.
The submerged landscape features forests of giant kelp (Macrocystis pyrifera) and red algae that create dense, labyrinthine structures. These kelp forests are complete ecosystems: they shelter fish, crustaceans, molluscs and invertebrates. Sea lion (Otaria flavescens) haul-outs are distributed across several islands within the ría.
At least 34 species of seabirds and coastal birds inhabit the area, including cormorants, gulls, terns and penguins. Commerson’s dolphins (Cephalorhynchus commersonii) — small black-and-white cetaceans — are one of the ría’s most distinctive and approachable species.
The Parque Interjurisdiccional Marino Isla Pingüino, accessible from Puerto Deseado, holds tens of thousands of penguins — including Magellanic and rockhopper species — active from October to April. It is recognised as one of Argentina’s “8 hidden natural wonders.”
Diving takes place at sheltered sites away from the main tidal channels. Tidal currents are the primary planning constraint: outings are timed around tides and the site requires solid current-management experience.
When to go
Best season is October to March, when penguin and other wildlife colonies are most active and weather conditions are most favourable. Commerson’s dolphins are present throughout much of the year.
How to get there
Puerto Deseado is reached via Route 281 (126 km from National Route 3) or National Route 3 from Caleta Olivia to the north (221 km) or Comodoro Rivadavia to the south. Distance from Buenos Aires is 2,204 km. There is no commercial airport in Puerto Deseado; the nearest with regular service is Comodoro Rivadavia.
Protected areas and regulations
The Ría Deseado was declared a Provincial Natural Reserve by decree in 1977, covering 10,000 hectares. In 2010 the provincial legislature established the Reserva Provincial Ría Deseado with formal legal status.
The Parque Interjurisdiccional Marino Isla Pingüino is jointly administered by the national and Santa Cruz provincial authorities. All activities within protected areas require coordination with Santa Cruz provincial wildlife authorities.
Commercial vessels and operators must hold Argentine Naval Prefecture authorisation.
Technical tips
All dive sites in the Ría Deseado are boat-access only — there is no shore diving. Diving here is still in its early stages: no established operators currently run regular scheduled dives, so it is worth contacting the local Naval Prefecture office or the Puerto Deseado municipality before planning a trip. Tidal currents are the main scheduling constraint; outings are timed around low tide to reduce drift at sheltered sites inside the estuary. Water is cold year-round — a drysuit or 7 mm semi-dry with hood and gloves is mandatory in every month. In winter (Jun–Aug) a drysuit is essentially compulsory. The underwater wildlife — fur seals, giant octopus, king crab — more than rewards the logistical effort.
Sources
- Wikipedia ES — Ría Deseado (geography, biodiversity, legal protection, kelp forests)
- Wikipedia ES — Puerto Deseado (geography, protected areas, fauna, access)
- CONICET CENPAT — La tonina overa, un pequeño delfín originario del mar Patagónico (Cephalorhynchus commersonii, distribution and Ría Deseado)
- APN — Biodiversidad Parque Interjurisdiccional Marino Isla Pingüino (rockhopper penguin, season Oct–Apr)