Resolving the militarised territorial dispute between Costa Rica and Nicaragua


A diplomatic intervention by the Organisation of American States prevented an armed conflict between Costa Rica and Nicaragua from erupting in 2010 and the International Court of Justice peacefully resolved the dispute in 2018.

The 1858 Treaty of Cañas-Jerez established the border between Costa Rica and Nicaragua as the San Juan River and provided stipulations for its use by both countries. However, differing interpretations of the Treaty have led to a series of disputes over territory along the border.1 Following several relatively minor incidents, the dispute flared up again in 2010 when the Nicaraguan military began dredging the river (which the Costa Rican government claimed was altering the border and damaging Costa Rican territory) and stationing troops on territory claimed by Costa Rica. The Government of Nicaragua justified such actions with another reinterpretation of nineteenth century treaties and the fact that Google Maps listed the territory as Nicaraguan.2 Although Costa Rica does not have a military, over 200 armed police were dispatched to the area in response to what the government called “an occupation.”3 In this uncertain context, there was every likelihood that an armed conflict would erupt.

Fearing the crisis would escalate, the Organisation of American States (OAS) called for both countries to withdraw their security personnel from the area and open a dialogue. When the Government of Nicaragua refused to withdraw its troops from the area, the OAS Secretary-General travelled to Costa Rica and Nicaragua to investigate the dispute and pressure the parties to resolve it peacefully.4 His visit was complemented by the promulgation of a formal OAS resolution requesting both countries withdraw armed personnel from the area and open a dialogue.5 With the Nicaraguan Government still refusing to withdraw its troops (and challenging the OAS’s right to make such demands), the Costa Rican government raised another case at the International Court of Justice (ICJ).6 The immediate crisis was mitigated in March 2011, when the ICJ ruled that both countries must refrain from sending personnel to the area.7 A more permanent resolution was issued in a 2018 ruling which judged much of the disputed territory to be Costa Rican (although a 3km strip of beach was awarded to Nicaragua), finalised the mutual maritime border, and stipulated that the Government of Nicaragua must pay compensation for environmental damage.8 Thanks in part to the preventive Diplomacy efforts of the OAS and the rulings of the ICJ, a potentially volatile territorial dispute was prevented from escalating into armed conflict.

1 Carin Zissis & David Schreiner. “A River Runs through It: The Costa Rica-Nicaragua Dispute.” Americas Society: Council of the Americas. (2010) Available at: (Accessed 09/11/2020)

2 Centre for Borders Research. “Boundary dispute between Costa Rica and Nicaragua involves Google maps.” Boundary news. (2010) Available at: (Accessed 09/11/2020)

3 Ibid.

4 OAS. “OAS Secretary General to Travel to Costa Rica and Nicaragua to Facilitate Dialogue.” Press Release. (2010) Available at: (Accessed 09/11/2020)

5 The Economist Intelligence Unit. “The political scene: Costa Rica-Nicaragua border dispute intensifies.” The Economist. (2010) Available at: (Accessed 09/11/2020)

6 ICJ. Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v. Nicaragua). (ICJ, 2020) Available at: (Accessed 09/11/2020)

7 Adam Williams. “International Court of Justice rules that Nicaraguan troops must leave Isla Calero.” The Tico Times. (2011) Available at: (Accessed 09/11/2020)

8 ICJ. Land Boundary in the Northern Part of Isla Portillos (Costa Rica v. Nicaragua). (ICJ, 2020) Available at: (Accessed 09/11/2020)

Start Year


End Year



Costa Rica

UN Regional Group

Latin America and the Caribbean

Type of Conflict

Risk of an interstate conflict

Type of Initiative

Diplomacy, Resolution of a militarised territorial dispute

Main Implementing Organisation(s)

The Organisation of American States and the International Court of Justice




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