João Vieira and Poilão Marine National Park is a national park in Guinea-Bissau. It was established in August 2000. It covers an area of 495.0 square kilometres and includes the uninhabited islands of João Vieira, Cavalos, Meio and Poilão, in the southeastern part of the Bijagós Archipelago. The beaches of the islands are frequented by the sea turtle species Chelonia mydas, Eretmochelys imbricata and Lepidochelys olivacea.