is a 1975 Japanese kaiju film directed by Ishirō Honda, written by Yukiko Takayama, and produced by Tomoyuki Tanaka and Henry G. Saperstein, with special effects by Teruyoshi Nakano. Distributed by Toho and produced under their effects subsidiary Toho–Eizo, it is the 15th film in the Godzilla franchise, serving as a direct sequel to the 1974 film Godzilla vs. Mechagodzilla and the penultimate entry of the Showa Era of the franchise, followed nine years later with The Return of Godzilla. It was the final film directed by series creator Ishirō Honda before his death.

Plot

Following the events of Godzilla vs. Mechagodzilla, Interpol agents search for Mechagodzilla's remains at the bottom of the Okinawan Sea in the hopes of gathering information on the robot's builders, the alien Simeons. However, their submarine is attacked by a giant, aquatic dinosaur called Titanosaurus and the crew vanishes.