If you’ve ever dreamed of a river journey that feels like slipping through a living, breathing jungle storybook, the Sierpe River is exactly that kind of magic. Winding its way from the lush heart of the Osa Peninsula, the Sierpe—named after the Spanish word for “serpent”—curves and coils through 48 kilometers of pure wild beauty before finally spilling into the Pacific Ocean. By the time it reaches the sea, the river stretches to more than a kilometer wide, opening up into an incredible natural gateway to one of the most biologically rich places on the planet.
This is no ordinary river. The Sierpe, along with its sister the Terraba River, flows through the Térraba-Sierpe National Wetlands—the largest continuous mangrove forest in Costa Rica and one of the biggest in all of Central America. These peaceful forests, made up of six resilient, salt-loving tree species, are teeming with life. Birds of all colors, mammals peeking through the branches, secretive reptiles, playful monkeys, and schools of fish weaving through the mangrove roots all call this place home. Every twist and turn of the river reveals another scene from nature’s playbook.
The small town of Sierpe marks the divide between the river’s wild upper reaches and its wide, open lower stretches near the river mouth, or “boca del río.” Though remote, Sierpe hums with quiet activity. Locals from the Osa Peninsula stop by to gather supplies, and travelers come to experience the mangroves up close—gliding silently by kayak, cruising on wildlife tours, or visiting local museums that celebrate the region’s cultural history. But here’s the thing: Sierpe is also the end of the road for most visitors. Beyond this point, the paved highways fade away, and the real adventure begins.
This is where Casa Roja finds its special place in the story. Perched right at the mouth of the Sierpe River, where the freshwater currents meet the salty embrace of the Pacific, Casa Roja stands at the crossroads of river, sea, and jungle. It’s not just a place to stay—it’s a front-row seat to one of Costa Rica’s wildest shows. From our doorstep, you can explore the winding mangroves, venture out to the open ocean, or disappear into the emerald jungles of the Osa Peninsula. Very few places in the world offer this kind of intimate access to such raw natural beauty. At Casa Roja, you’re not just visiting the Sierpe River—you’re living it.
