Monsterland and Monster Island - Monster Island

Monster Island first appeared in 1969's All Monsters Attack, in the dreams of a young boy named Ichiro. He dreamt of befriending Minilla and watching him and Godzilla battle other monsters. In the dream, the daikaiju living on Monster Island included Godzilla, Minilla, Gabara, Kamacuras (3 of them), Kumonga, Ebirah, Anguirus, Gorosaurus, Manda, the Giant Condor from Godzilla vs. the Sea Monster, Maneater (a plant man that grabs Ichiro in the jungle, and Rodan (mentioned but unseen).

Monster Island is revealed to be an actual island in Godzilla vs. Gigan (1972). Godzilla, Rodan, Mothra, Anguirus, Minilla, Gorosaurus, Kumonga, Manda, and Kamacuras all live there.

Monster Island appeared again in Godzilla vs. Megalon (1973), one of many locations suffering the effects of nuclear testing. This is seen to disturb Godzilla, Rodan, and Anguirus; as they try to escape the explosions, Anguirus falls into a crevasse in the ground. Rodan's fate was never revealed, though it can be assumed he flew away safely. Godzilla was summoned from Monster Island in a few of the episodes of the television series Zone Fighter, to assist the giant superhero, specifically the first episode that Godzilla appeared in. These Zone Fighter episodes are considered by Toho to be canon.

It is commonly speculated to be Solgell Island from Son of Godzilla due to the timing of introduction and presence of Godzilla, Minilla, Kamacuras and Kumonga, all kajiu who had been previously seen on the island whereas most other kajiu had not had set locations of origin. As well, the island is referred to as "Monster Island" in the Japanese version of the film, most notably the title.