Kluwer: Costa Rica’s First Investment Arbitration Set-Aside Proceeding and the End of the Investor-State Exclusion

In September 2026, the First Chamber of the Supreme Court of Costa Rica (“Sala Primera”) issued the first decision by a Costa Rican court on the annulment of an investment arbitration award. The case, Castillo Bozo v. Panama, put an unusual feature of Costa Rica’s arbitration legislation under direct scrutiny: the now-repealed International Commercial Arbitration Law expressly excluded Costa Rica as a seat for investor-State arbitration.