Recent development in electronic devices allow analysis of 3D movements of marine animals at spatio-temporal scales of metres and seconds. We report the discovery of analogous circling movements observed across marine megafauna, including sharks (Galeocerdo cuvier, N = 8; Rhincodon typus, N = 1), sea turtles (Chelonia mydas, N = 3) and marine mammals (Arctocephalus gazelle, N = 8, Ziphius cavirostris, N =1). It shared common characteristics that animals circled at relatively constant speed for > 2 circles although there were some variations in situations where animals circled (e.g. during dives, at sea surface etc.). A striking example was recorded by a homing turtle when it approached to its destination, the nesting beach: it circled just like a machine anticlockwise for 29 min (76 circles, mean cycle = 21.0 s), followed by a 12 min clockwise circling (35 circles, mean cycle = 17.7 s). The turtle selected appropriate direction toward its destination after circling movements, implying its possible association with navigation. Given that circling movements were observed across different taxa, it might be a behavioral convergence. Further study examining high-resolution 3D movements in relation to animals’ internal states and environmental factors would help understanding the function of circling movements.