The capture of the frigate Esmeralda was a naval operation conducted on the nights of 5 and 6 November 1820. A division of boats with sailors and marines of the First Chilean Navy Squadron, commanded by Thomas Cochrane, stealthily advanced towards Callao and captured the ship through a boarding attack. Esmeralda was the flagship of Spanish fleet and the main objective of the operation. She was protected by a strong military defense that the royalists had organized in the port.