Anak Krakatoa () is an island in a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. On December 29, 1927, Anak Krakatoa emerged from the caldera formed in 1883 by the explosive volcanic eruption that destroyed the island of Krakatoa. There has been sporadic eruptive activity at the site since the late 20th century, culminating with a large underwater collapse of the volcano which caused a deadly tsunami in December 2018, followed by subsequent activity in 2019 and an eruption in April 2020. Due to its young age, the island is one of several in the area which are of considerable interest to volcanologists, and the subject of extensive study.