The film stars Akira Takarada, Yuriko Hoshi, Hiroshi Koizumi, Kenji Sahara, and Emi and Yumi Itō, with Haruo Nakajima and Katsumi Tezuka as Godzilla.

At Tsuburaya's insistence, Toho purchased an Oxberry 1900 optical printer to remove damages in composite photography shots.

An edited version titled Godzilla vs. the Thing was released by American International Pictures in the United States on August 26, 1964.

The following morning, reporter Ichiro Sakai and his photographer Junko Nakanishi find a strange blue-gray object amongst the wreckage.

At a local hotel, Sakai, Junko, and Miura discuss how to legally counter Kumayama's plans, and find him at the lobby.

Kumayama meets with his financial backer Jiro Torahata, who reveals his plans to build the Shizunoura Happy Center around the egg.

They are visited by the Shobijin, tiny twin fairies, who attempt to convince them to return the egg but have to escape when the businessmen try to capture them.

The Shobijin run into Sakai, Junko, and Miura, and reveal to them that the egg belongs to the colossal insect god Mothra, the recent typhoon caused it to wash up on Japanese waters, and destruction will follow when the larva emerges.

The trio return to Kurata beach to investigate further, but the giant reptilian monster Godzilla emerges from the buried mud.

The Shobijin and natives refuse, seeing it as divine retribution on outsiders for ravaging their island with nuclear tests, and not returning the egg.

Junko and Sakai plead that the innocent are also in danger, that they have no right to decide who deserves to live or die, and that civilization is flawed, but is trying hard to make the world better.

[10] Honda purposely chose to portray the film's version of Infant Island as a partial wasteland as a way to "visualize the terror and the power of the atomic bomb".

[10] Tanaka cast the twin sisters Emi and Yumi Itō as the Shobijin due to their popularity as the singing duo The Peanuts, as this would create publicity for the film.

[21][22] For the 1980 re-release, the Japanese pop and rock band Talizman recorded a new song simply titled "Godzilla", which was later included as a bonus feature on Toho's 2014 Blu-ray.

[24] The Godzilla suit was constructed by Teizo Toshimitsu two months prior to filming, with input from the actor Haruo Nakajima whenever he visited the workshop.

[31] The larva movements were designed by Soujiro Iijima and used a conveyor belt with rotating gears that allowed the bodies to move up and down.

[24] Honda originally intended to depict the wasteland part of Infant Island with more realism and graphic imagery but this idea was dropped due to budgetary issues with the art department.

He attempted to salvage the shot by having Godzilla appear enraged by the Castle's strong fortification, but the filmmakers chose to re-shoot the scene with a rebuilt model designed to crumble more easily.

[40] For the opening typhoon scene, Iijima built a shallow water tank to create the illusion of violent waves.

[41] Rubber glue was blown onto Godzilla's suit by an electric fan for the scene where Mothra's larvae entrap him in silk.

[1] The American version of the film received only a few minor adjustments: the Shobijin song on Infant Island was shortened as was a scene where Sakai, Junko Miura and Makamura wave goodbye to the Mothras swimming home.

[54] A 1964 review for Kinema Junpo praised the effects but criticized the military attacking Godzilla, writing, "It's strange that the people don't learn from the past.

"[11] In a contemporary review from the Monthly Film Bulletin, the critic wrote that "In spite of some clumsy model shots, Godzilla's fight with the giant moth and its caterpillar progeny is one of Toho's better efforts".

[55] The critic praised Godzilla's design in the film and wrote that the "ineffectual attempts to bring him to a halt are cleverly and spectacularly staged.

Unfortunately, nothing else quite matches the special effects", writing that the plot is "ridiculous" and the acting "lamentable, and the two miniature twins' habit of repeating every line of dialogue simultaneously is intensely irksome".

The review said that the "virtually all-Japanese cast, with unfamiliar faces and broad emoting typical of such Japanese pics, also detracts from general appeal".

"[57] In 2017, Ryfle and Godziszewski gave their impression that "[t]he final twenty-plus minutes hint at the genre's impending tilt toward young boys.

It's a near nonstop barrage of military hardware and monster action", and added that "Honda seemed to know that kids were now rooting for Godzilla, and so the film never gets too scary".

Ryfle said that the English script was "snappy" and "well written" and that the voice performances sounded sincere and pulled with effort, stating, "You'd be hard pressed to find another movie where the dubbing is done as well as it is here.

[65] In 1989, the American version was released on VHS in North America by Paramount Home Video under the title Godzilla vs. Mothra.