We report the occurrence of a lone humpback whale (Megaptera novaeangliae) calf inside Baía de Todos os Santos, north-eastern Brazil, encountered swimming near the shore at a busy beach of the city of Salvador. The calf was monitored for over six hours during which time it was photographed performing an unusual behaviour, interpreted by the authors as a sign of stress and disorientation. One week later, a dead humpback whale calf was found 14 km north-east, on the island of Itaparica. Due to the similar size and the oceanographic currents of the area, we considered it to be the same animal. Finally, we discuss considerations to improve conditions for the rescue of cetaceans in the future.