Article 12 of the Constitution of Costa Rica
The Article 12 of the Constitution of Costa Rica abolishes Costa Rica's army as a permanent institution, making Costa Rica one of the first countries in the world to do so as the current Constitution was enacted in 1949. Costa Rica is one of the few countries without armed forces and, alongside Panama, one of the few that is not a microstate.
Source: Wikipedia — Article 12 of the Constitution of Costa Rica (CC BY-SA 4.0)