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Travel back in time and through the largest mangrove biome in Central America, one of 13 different ecosystems present on the Osa Peninsula. Enjoy a leisurely walk through centuries-old artfiacts, followed by a relaxing boat ride through Sierpe River’s winding mangroves.  

Tours start and finish in Puerto Jimenez.

Prices are based on a minimum of two people. Contact us to inquire about about available dates, and half-day or night tours. 

Sierpe River’s Mangrove and Sphere Museum Tour 

What’s Included 

What’s not Included 

Mystery and Majesty: Sierpe River Mangroves & Pre-Columbian Stone Spheres

Journey deep into Costa Rica’s southern frontier with a tour that pairs natural wonder with ancient mystery. Begin your adventure on the Sierpe River, where you’ll drift through Central America’s largest mangrove forest, a protected Ramsar wetland teeming with life. Navigate a maze of roots and waterways beneath towering trees while your guide points out crocodiles, tree boas, and Jesus Christ lizards darting across the water. Overhead, flocks of scarlet macaws, herons, and kingfishers bring the jungle to life with movement and color.

But the magic doesn’t stop at the river’s edge.

Just inland lies Finca 6, home to the enigmatic stone spheres of the Diquís culture, crafted between 300 BCE and 1500 CE. These nearly perfect granite orbs—some weighing over 15 tons—have baffled archaeologists for decades. Believed to mark important ceremonial sites or celestial alignments, they offer a rare glimpse into the engineering and symbolism of a lost civilization. At the open-air museum, you’ll wander among original spheres in their archaeological context, gaining insight into Costa Rica’s pre-Columbian heritage.

Whether you’re a birdwatcher, history buff, or simply curious, this tour invites you to experience both the wild beauty and cultural richness of the Osa region. It’s a journey through time and nature—where jungle roots and ancient stones reveal stories still echoing through the trees.

Sierpe, Costa Rica: Where Jungle Meets Ancient Mystery

Nestled in the lush southern Pacific region of Costa Rica, the small town of Sierpe is a hidden gateway to some of the country’s most extraordinary natural and cultural treasures. Often overlooked in favor of more famous destinations, Sierpe offers travelers a chance to step off the beaten path and into a world where dense mangrove forests, rich biodiversity, and pre-Columbian history come together in one unforgettable place.

The town itself is peaceful and charming, situated along the Sierpe River, which winds its way toward the Pacific Ocean. While Sierpe may look unassuming at first glance, it is the starting point for boat tours that explore the largest and most intact mangrove ecosystem in Central America—the Terraba-Sierpe Wetlands, a UNESCO Ramsar site. This vast network of tidal waterways, roots, and canopies serves as a nursery for marine life and a sanctuary for hundreds of species, including monkeys, crocodiles, caimans, sloths, and countless tropical birds. Wildlife sightings are frequent, and the setting itself—calm waters beneath emerald tunnels of vegetation—is tranquil and awe-inspiring.

In addition to its ecological importance, the Sierpe region is also a place of deep cultural significance. Just a short drive or boat ride from town lies Finca 6, part of the Diquís Delta archaeological zone, and home to the famous stone spheres of Costa Rica. These mysterious, perfectly rounded granite spheres were crafted by the Diquís people over 1,000 years ago and have puzzled archaeologists for decades. Some weigh several tons and were precisely placed in patterns, often aligned with astronomical events or important ceremonial locations. Today, Finca 6 Museum offers the rare chance to see these spheres in their original context—still resting in the ground as they were found—surrounded by the dense tropical forest that has kept them hidden for centuries.

The combination of rich biodiversity and ancient human history makes Sierpe a remarkable destination for travelers who want more than just beautiful scenery. Here, you can float past crocodiles in the morning, sip fresh coconut water in a quiet riverside village by midday, and stand beside pre-Columbian monuments by afternoon. Whether you’re a nature enthusiast, a photographer, a history lover, or simply someone seeking a quieter, more meaningful travel experience, Sierpe has something to offer.

From Sierpe, visitors can also connect to larger adventures—boat trips to Corcovado National Park, Caño Island, or the beaches of Drake Bay. But the charm of Sierpe lies in staying a while: learning about the plants used by local communities for generations, tasting fresh-caught seafood, or just watching scarlet macaws fly over the river at dusk.

Sierpe invites you to slow down, explore deeply, and experience a side of Costa Rica that most travelers never get to see—a place where nature and history speak in quiet, unforgettable ways.

Sierpe River and Spheres Museum Itinerary

6:00 AM: Meet your guide at the agreed meeting point 

2:30 AM: Arrive in at the Sierpe river dock

What to bring on your adventure

  • Water shoes
  • Light and quick dry clothes, and/or change of clothes in case you get wet
  • Hat and sunglasses
  • Sunblock
  • Bug repellent

Optional:

  • Waterproof bag
  • Binoculars
  • Camera
  • Sunglasses
  • Handkerchief