In early 1940 "Dunedin" was operating in the Caribbean Sea, and there she intercepted the German merchant ship "Heidelberg" west of the Windward Passage. "Heidelberg"s crew scuttled the ship before "Dunedin" could take her. A few days later, "Dunedin", in company with the Canadian destroyer , intercepted and captured the German merchant ship "Hannover" near Jamaica. "Hannover" later became the first British escort carrier, . Between July and November, "Dunedin", together with the cruiser , maintained a blockade off Martinique, in part to bottle up three French warships, including the aircraft carrier .