A Boat Ride down the Rio San Juan 

San Carlos is at the mouth of the Río San Juan and the departure point for a breathtaking river journey 70km (43 miles) downriver to the old historical fort town of El Castillo. The truly adventurous can hire a boat to continue another 140km (87 miles) to the lonely Caribbean port town of San Juan del Norte, passing Reserva Biológica Indio Maíz on the way. Birdlife is abundant along the riverbanks, with large flocks of egrets and cormorants swirling overhead or floating down the mirror-like waters on floating clumps of water hyacinth. Look out for the occasional kingfisher and the large silver fish called a tarpon, which slips through the water like a dolphin, known locally as sábalo. This river journey is interrupted by several stops to pick up and drop off people at small settlements on the way to the fort. The occasional boat even pulls up alongside the colectivo to sell food, drinks, and fresh fish stored in ice boxes.

Boca de Sábalos is a muddy little settlement of 1,200 people with two decent hotels and a 2,000-hectare (4,942-acre) palm-oil farm and factory. As the town's name implies, it is an excellent place for fishing sábalo that can be as long as 2.5m (8 1/4 ft.). There is also a local version of the snook fish called róbalo, which is very popular as a dish.


Beyond El Castillo, the rapids known as Raudal el Diablo are easily negotiated by an experienced boatman, and the location is a popular fishing spot with locals. The wild jungle of Reserva Biológica Indio Maíz contrasts with bare ranchland on the opposite Costa Rican side. A sunken steamship lies in the mouth of the Río Samoso whilst crocodiles and turtles sunbathe on the sandbanks. Tiny waterways lead to dark grottoes. Giant palms and drapes of vines hang from gigantic cedar trees. At the Río Sarapiquí, there is a border checkpoint and small settlement. This was Contra territory in the 1980s. Past several more tributaries, the river turns north as it approaches the sea, then meanders through wetlands and swamp. A broad beach appears, separated by a long sandbar known as La Barra. Bull sharks lie in the estuary and along the shore feeding on the many fish, meaning this is not a good place to swim.

A series of connected waterways and estuaries to the north are known as Bahía de San Juan. An old dredger lies abandoned in the water, a reminder of human plans to turn this river into a canal. The high-end lodge Río Indio is located here, close to a spectacular river of the same name. The blue waters of the waterway are excellent for fishing and exploring.

Greytown lies abandoned at the edge of a waterway. This derelict ghost town was named after a British governor of Jamaica and had a tumultuous history of English invasion, Nicaraguan possession, and U.S. bombing before it became a steamship boomtown and finally a ragged Contra stronghold. The Sandinistas burned it down in 1982, and the only interesting thing to see is its fascinating jungle-covered cemetery. The 19th-century tombs are segregated by race, and the graveyard is now a national monument. A new settlement was recreated upriver, an uninteresting swamp town called San Juan del Norte. Here, you have finally reached the end of the line, with nothing more but the vast rainforest on one side and the Atlantic on the other.


El Castillo

The dark-stained stone remains of the Spanish fort El Castillo de la Inmaculada Concepción de María remind one of a Maya temple. It's a relic of just how important the river was as a gateway between Europe and Central America. The Spanish built several forts along the river to deter marauding pirates bent on raiding prosperous Granada. El Castillo was the biggest, and was constructed between 1673 and 1675. It is Nicaragua's oldest Spanish building still in its original state. The fort is situated on a river bend and sits high over a cluster of stilted houses with red tin roofs and has an excellent view downriver.

In its heyday, it was a formidable obstacle, with 32 cannons trained on any strangers with malice coming this way and a well-stocked armory of 11,000 weapons. It was the scene of many skirmishes and sieges, and the British navy tried several times to take it. In 1762, they laid siege to the fort for 5 days. A captain's daughter called Rafaela Herrera became a national hero when she rallied the troops and lead the defense, breaking the British attack by sending burning flotsam downstream towards the enemy ships and thus breaking their formation. The British tried again in 1779 when seven warships carrying 1,000 troops gathered at the river mouth. A young, unknown captain named Horatio Nelson decided to attack the fort from the jungle behind and successfully took it. However, the Spanish then laid siege, and disease and desertion forced the British to abandon their prize.


There is now a well-stocked and interesting Museo that explains the fort's swashbuckling heritage (in Spanish). Cannonballs and old rum bottles add color to the story. It is open daily from 8am to noon and 1 to 5pm. There is a single entrance fee of C40. Centro de Interpretación de la Naturaleza is another museum behind the fort that showcases the area's flora and fauna. It is open daily from 10am to 4pm.

Reserva Biologica Indio-Maiz

A rainforest needs a lot of rain. Five meters (197 in.) fall on this reserve a year, making it one of the wettest places on Earth. Not that you'd notice. The 50m-high (164-ft.) trees support an intricate canopy of vines and creepers that crawl up towards the sun, creating a dense canopy umbrella. The abundance of water gives the canopy that lush greenness and provides humidity for fungi to thrive and frogs to flourish. There are 300 species of reptiles and amphibians in this mega park, the second-biggest reserve and largest primary rainforest in Central America. The dark slopes of several volcanoes make this appear as the perfect spot to shoot a King Kong movie. But who needs giant apes when there are 200 species of mammal here, including tapir, deer, and big cats? There are 600 species of birds, including hummingbirds, kingfishers, toucans, flycatchers, and woodpeckers. Indio-Maíz is an ecological blockbuster, but there are zero facilities, and it requires a guide to visit. It is bordered by the Río Bartola in the west and the Caribbean in the east. Check at the Managua MARENA office regarding access or book with a specialist tour agency.


Dead in the Water: The Nicaragua Canal

The question here for almost 500 years was whether an inter-oceanic canal could be built through Nicaragua. Nowadays the question is why it never was. Geographically, Nicaragua is perfect for such a momentous waterway. It is the lowest point in the entire Americas, and because Lago de Nicaragua runs into the Caribbean via the broad Río San Juan, the Pacific is just a tantalizing 18km (11 miles) from the lakeshore. Thus, a relatively minor bit of excavation would split South America from North America. Such a project would have had a major effect on the country politically, economically, and environmentally. It is fascinating to see how the Gibraltar of the Americas never came to pass.

It was certainly not from lack of interest. King Philip of Spain ordered a feasibility study back in 1567. The British attacked Nicaragua in the 17th century with the intent of "dividing the Spanish Empire in half." Napoleon Bonaparte III formed the Nicaraguan Canal Company in 1869 but was deposed before he could start digging. The Belgians and Dutch sniffed around, as did Cornelius Vanderbilt, who commissioned the first systematic survey in 1852. An American firm called the U.S. Maritime Canal Company sent a dredger to the mouth of the Río San Juan in 1893. The company went bankrupt, and the boat was abandoned in San Juan del Norte, where it can be seen to this day, a rusting relic. In 1901, the U.S. House of Representatives voted in favor of building a canal through Nicaragua, much to the annoyance of Panama. It looked at last like the project was finally getting off the ground. However, a volcano eruption and some clever scare tactics by the Panamanian lobbyists saw the U.S. Senate vote the motion down. The project went to Panama.


In 1914, the U.S. signed a treaty with Nicaragua in which it was given the exclusive rights "in perpetuity" to build a canal. Washington had no intention of ever doing so, but neither did it want the French or Japanese to step in and rival the Panamanian project. The canal dream was over.

Since then, there has been a revival in interest in building a canal; the treaty was revoked in 1970. A $2-billion "dry canal" was proposed in the 1990s, linking the oceans by a cargo railway line. Other project ideas include a $20-billion Panama-style canal and a $50-million shallow barge waterway known as an Ecocanal. So far, such schemes have remained on the drawing board, and as you survey the splendor of the Río San Juan, you cannot help hoping they stay that way.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.