Coup Atlas Research Database
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09412111948AttemptedDissident coup

Costa Rica, 1948 — dissident coup attempt

Costa Rica (CRI)Central America, AmericasDecember 11, 1948

Event Summary

On 10 to 11 December 1948 armed Calderonista exiles invaded northwestern Costa Rica from Nicaragua in a bid to overthrow the Founding Junta of the Second Republic headed by Jose Figueres Ferrer, opening the Costa Rica Nicaragua crisis of 1948 to 1949. The invaders, followers of former president Rafael Angel Calderon Guardia defeated in that year's civil war and sheltered by Nicaraguan strongman Anastasio Somoza Garcia, struck just days after Figueres had symbolically abolished the army on 1 December 1948. The junta mobilized volunteers, Figueres personally led forces into Liberia on 17 December, and by late December the invaders had been beaten at El Amo and La Cruz and driven back toward the border.

Costa Rica invoked the new Rio Treaty and an Organization of American States commission investigated Somoza's role in the invasion, which collapsed without unseating the junta.

Researched Details

Researched

Independent research, added record by record. Hover any label for what it means.

Target identified in Coup Atlas research: Junta president Jose Figueres Ferrer survived the invasion unharmed and the junta completed its term, handing power to Otilio Ulate in 1949
RESEARCHED NAME
Key figures
Jose Figueres Ferrer (junta president, target)
Rafael Angel Calderon Guardia (exiled former president behind the invasion)
Anastasio Somoza Garcia (Nicaraguan ruler harboring the invaders)

Sources

On December 10, 1948, armed Calderonista rebels exiled in Nicaragua invaded Costa Rica but were repulsed, and the Organization of American States sent a commission to investigate Somoza's involvement.
SOURCE REVIEWED OnWar, Calderonista Invasion of Costa Rica 1948 open source ↗
The Costa Rica Nicaragua crisis of 1948 to 1949 began on December 10, 1948, when Calderonistas harbored by Somoza after the civil war invaded, amid a cycle of charges between Figueres and Somoza that the other intended to attack.
SOURCE REVIEWED Old Dominion University master's thesis, Peaceful Collaboration open source ↗
On December 17 Figueres personally led a battalion of volunteer government forces into Liberia in Guanacaste to attack the invaders, and after fierce fighting El Amo fell on December 22 and La Cruz two days later, with the invaders fleeing.
SOURCE REVIEWED SensorialSunsets, Abolition of the Army and Defense of Costa Rica's Sovereignty open source ↗
The invasion came days after the junta abolished the army on 1 December 1948, with Figueres symbolically smashing a wall of the Bellavista Barracks and handing the site over for a museum.
SOURCE REVIEWED SensorialSunsets, Abolition of the Army and Defense of Costa Rica's Sovereignty open source ↗

Editorial Note

Dataset date 11 December 1948 falls within the invasion that began 10 December; treated as the same event. First armed test of Costa Rica after army abolition and first practical invocation of the inter American system for the junta; pairs with the Cardonazo of April 1949 and the later 1955 Calderonista invasion.

Cross-Reference

Only one dataset carries it. One of the three reference datasets we check against carries this event; the others do not list it. That is not a contradiction — the datasets cover different periods and use different thresholds — but it means the record has had less outside corroboration.

Identifiers for finding this same event in the other datasets:

Cline Center id
09412111948

How the match is made is described in crossref-report.md.

Outcome and Target

Coup Atlas research identifies the target as: Junta president Jose Figueres Ferrer survived the invasion unharmed and the junta completed its term, handing power to Otilio Ulate in 1949.

Baseline coding: Coup attempt failed to remove the incumbent. Recorded leader fate: remained in office; not physically harmed. The baseline file does not name individual targets; researched names are kept in a separate layer.

Baseline Dataset Citation
Cline Center Coup d’État Project Dataset, v2.2.2
Peyton, Buddy, Joseph Bajjalieh, Michael Martin, and Andrea Gerald. 2026. Cline Center Coup d’État Project Dataset. Cline Center for Advanced Social Research. V.2.2.2. February 17. University of Illinois Urbana-Champaign. doi: 10.13012/B2IDB-9651987_V10
Open dataset DOI ↗
⚑ This citation establishes the coded baseline record; use the claim-level sources above for the researched narrative.

Baseline Source-Document Entries

CSP

Named in the baseline source document; no article citation was recorded.

New York Times

“Costa Rican Invasion-Revolt Strikes at Figueres’; Regime Nicaragua Is Attack Base – Envoy Here Invokes Rio Defense Pact COSTA RICA REVOLT HITS AT FIGURES,” December 12, 1948

This is the citation trail carried by the baseline dataset, grouped by outlet and rejoined from the line-wrapped original. Coup Atlas has not independently re-checked every document; read the original before citing a specific claim. URLs the import damaged beyond safe repair are shown as plain text and listed in citations-report.md. How this list is built →

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Related Records

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