People from the public and private sectors on Okinoerabu Island in Kagoshima Prefecture, are tackling the issue of marine plastic waste. In 2019, the island became the host town of the Caribbean island nations of Dominica and Grenada. People from those countries visited Okinoerabu for an environmental meeting also attended by researchers studying the issue. Local schoolchildren impressed the experts with their study of microplastics. We learn how the people of Okinoerabu and these 2 nations are dealing with this issue.