A moon base is destroyed by a spaceship from Zigra which is looking to take over the planet earth to use its oceans for its ocean-dwelling denizens. Gamera must once again come to the aid of the human race while all of Japan roots him on.
| Actor | Role |
|---|---|
 Eiko YanamiWoman X / Chikako Sugawara | Woman X / Chikako Sugawara |
 Reiko KasaharaKiyoko Ishikawa | Kiyoko Ishikawa |
 Mikiko TsubouchiMrs. Ishikawa | Mrs. Ishikawa |
 Kōji FujiyamaDr. Tom Wallace | Dr. Tom Wallace |
| IIsamu SaekiDr. Yosuke Ishikawa | Dr. Yosuke Ishikawa |
| SShin MinatsuSea World Staff | Sea World Staff |
| AArlene ZoellnerMargie Wallace | Margie Wallace |
| GGloria ZoellnerHelen Wallace | Helen Wallace |
| YYasushi SakagamiKeinichi Ishikawa | Keinichi Ishikawa |
 Keiichi NodaZigra (voice) | Zigra (voice) |