San Juan River (Nicaragua) in the context of "Nicaraguan Canal and Development Project"

Attempts to build a canal across Nicaragua to connect the Atlantic Ocean and the Pacific Ocean stretch back to the early colonial era. Construction of such a shipping route—using the San Juan River as an access route to Lake Nicaragua—was first proposed then. Napoleon III wrote an article about its feasibility in the middle of the 19th century. The United States abandoned plans to construct a waterway in Nicaragua in the early 20th century after it purchased the French interests in the Panama Canal, which has served as the main connecting route across Central America since its completion.

Because the steady increase in global shipping may eventually make the project economically feasible, speculation on a new shipping route has continued. In June 2013, Nicaragua's National Assembly approved a bill to grant a 50-year concession to the HK Nicaragua Canal Development Investment (HKND) to manage the Nicaraguan Canal and Development Project to build the canal, but little development took place, and the concession to HKND was cancelled in May 2024.

Lake Nicaragua or Cocibolca or Granada (Spanish: Lago de Nicaragua, Lago Cocibolca, Mar Dulce, Gran Lago, Gran Lago Dulce, or Lago de Granada) is a freshwater lake in Nicaragua. Of tectonic origin and with an area of 8,264 km (3,191 sq mi), it is the largest fresh water lake in Central America, the 19th largest lake in the world (by area) and the tenth largest in the Americas, slightly smaller than Lake Titicaca. With an elevation of 32.7 metres (107 ft) above sea level, the lake reaches a depth of 26 metres (85 ft). The intermittent Tipitapa River feeds Lake Nicaragua when Lake Managua has high water. Lake Cocibolca is between two other bodies of water, on top is Lake Xolotlán and below is the San Juan River. These body of waters complete the largest international drainage basin in Central America.

The lake drains via the San Juan River flowing east to the Caribbean Sea, historically making the city Granada on the northwest shore an Atlantic port, although Granada (as well as the entire lake) is closer to the Pacific Ocean geographically. The Pacific is near enough to be seen from the mountains of the largest island in the lake, Ometepe. The lake has a history of Caribbean pirates who assaulted Granada on three occasions. Before construction of the Panama Canal, a stagecoach line owned by Cornelius Vanderbilt's Accessory Transit Company connected the lake with the Pacific across the low hills of the narrow Isthmus of Rivas. Plans were made to take advantage of this route to build an Interoceanic Canal, the Nicaragua Canal, but the Panama Canal was built instead. In order to quell competition with the Panama Canal, the U.S. secured all rights to a canal along this route in the Bryan–Chamorro Treaty of 1916. However, since this treaty was mutually rescinded by the United States and Nicaragua in 1970, the idea of another canal in Nicaragua still periodically resurfaced, such as the Ecocanal proposal . In 2014, the government of Nicaragua offered a 50-year concession to the Hong Kong Nicaragua Canal Development Investment Company (HKND) to build a canal across Nicaragua at a cost of US$40 billion, with construction expected to begin in December 2014 and complete in 2019. Protests against the ecological and social effects of the canal as well as questions about financing led to doubts about the project, and in the end construction never began.