The Tropical Islands are an area on Earth located east of Papaya Island. It is where Piccolo fought Android 17, and where Cell absorbed Android 17 and Android 18.
The Tropical Islands were named in the video game Dragon Ball Z: The Legacy of Goku II. Enemies encountered here are a Mercenary Clan, Sabertooth Tigers, and Alligators. It is also where the Seven-Star Dragon Ball is located.