There were three Avenger class escort carriers in service with the Royal Navy during the Second World War and one ship of the class in the United States Navy called the Charger Type of 1942 class escort carrier. All three were originally American merchant ships in the process of being built at the Sun Shipbuilding and Drydock Company Chester, Pennsylvania. The ships laid down in 1939 and 1940 were launched and delivered to the Royal Navy by 1942.