Sirena, the remote ranger station at the heart of Corcovado National Park, is taking visitors in bigger numbers again. From September 17, Costa Rica's park authority SINAC raised the daily cap at Sirena to 366 people — a jump from the 225 limit imposed in July while the station sorted out a messy wastewater problem.
The breakdown: 230 spots go to day visitors, 105 to overnight guests, and the remaining 31 are held for the local permit holder and the Osa Conservation Area administration. The increase was signed off once the station met health requirements and repaired its wastewater treatment system, which inspections had found poorly maintained and unable to cope with peak crowds. At its worst, untreated waste was reportedly flowing into a waterway inside the park.
The July restrictions hit the Osa Peninsula hard. Guides, boat operators, hotels and restaurants there lean heavily on Corcovado traffic, and Sirena is the park's crown jewel — one of the best places in Costa Rica to see tapirs, all four monkey species, scarlet macaws, peccaries and, if you're lucky, a jaguar or puma.
One catch for anyone booking now: Sirena, along with the El Tigre and Los Patos sectors, closes for the whole of October — standard annual maintenance plus some of the wettest weather of the year on the Osa. San Pedrillo and La Leona stay open through that month. Day-to-day caps elsewhere in the park stand at 120 for San Pedrillo and 80 each for La Leona, Los Patos and El Tigre.
The story isn't entirely wrapped up. The Environment Ministry has asked Costa Rica's Constitutional Chamber for more time to comply with a court ruling demanding scientific evidence that current visitor levels won't damage the park's ecosystems — especially since earlier rules tied overnight increases specifically to proof the wastewater system could take the load. With around 115,000 visitors in 2025, Corcovado sits at a tricky crossroads between conservation and the tourism economy that the Osa's communities depend on.
For travellers, the practical takeaway is simple: from November you can once again plan day trips or overnight stays at Sirena with far more availability than mid-summer, but October trips should target San Pedrillo or La Leona instead.
