Terror of the Tsunami Monsters, Tokyo's Big Pinch (津波怪獣の恐怖 東京大ピンチ Tsunami Kaijū no Kyōfu Tōkyō dai Pinchi) is the thirteenth episode of Return of Ultraman and the first entry to the Terror of the Tsunami Monsters arc. A theatrical version with episodes 13-14 combined came out as Return of Ultraman: Fear of the Tornado Monsters (帰ってきたウルトラマン竜巻怪獣の恐怖 Kaettekita Urutoraman Tatsumaki Kaijū no Kyōfu) on December 12, 1971 at the Toha Champion Festival along with other movies like Ghidorah, the Three-Headed Monster, renamed as Godzilla, Mothra, King Ghidorah: Earth's Greatest Battle and a shorter version of it, Inakappe Taishō's movie, The Adventures of Hutch the Honeybee, and The Little Match Girl.
A vessel transporting gemstones was attacked by legendary monster Seamons and sunk into the sea. Captain Takamura was liable for the case, but his memory was lost. MAT started making analysis if "The Song of Seamons" sung by Captain Takamura before the incident, hoping to get some clues. However, Seamons appeared with Seagorath and together they created a great tsunami.
- Hideki Go (郷秀樹 Gō Hideki): Jiro Dan (団 時朗 Dan Jirō)
- Katsushiro Kato (加藤勝一郎 Katō Katsuichirō): Nobuo Tsukamoto (塚本信夫 Tsukamoto Nobuo)
- Takeshi Minami (南猛 Minami Takeshi): Shunsuke Ikeda (池田 駿介 Ikeda Shunsuke)
- Ippei Ueno (上野一平 Uneo Ippei): Hatashi Mitsushi (三井 恒 Mitsushi Hatashi)
- Yuriko Oka (丘ユリ子 Oka Yuriko): Mika Katsuragi (桂木美加 Katauragi Mika)
- Fumio Kishida (岸田文夫 Kishida Fumo): Ken Nishida (西田健 Nishida Ken)
- Narrator (ナレーター Nareta): Akira Nagoya (名古屋章 Nagoya Akira)
- Captain Takamura (高村船長 Takamura Sencho): Akiji Kobayashi (小林昭二 Kobayashi Akiji)
- Yoko Takamura (高村陽子 Takamura Yōko): Keiko Nishiyama (西山恵子 Nishiyama Keiko)
- Goichiro Funayama (船山豪一郎 Gōichirō Funayama): Hiroshi Hasegawa (長谷川弘 Hasegawa Hiroshi)
- Kobacho Akagi (赤木工場長 Agaki Kōbachō): Hiroyuki Nishimoto (西本裕之 Nishimoto Hiroyuki)
- Self-Defense Forces commander (自衛隊指揮官 Jieitai Shikikan): Junichiro Mukai (向井淳一郎 Mukai Jun'ichirō)
- Kawasaki Steering Mechanic (川崎操舵士 Kawasaki sōda-shi): Eiichi Kikuchi (菊池英一 Kikuchi Eiichi)
- Sea God Round Sailor (海神丸船員 Kaijinmaru sen'in): Shoei Tojo (東條昭平 Tōjō Shōhei) (cameo appearance)
- Kijima (木島 Kijima): Munemaru Koda (幸田宗丸 Koda Munemaru)
- Ultraman (ウルトラマン Urutoraman): Eiichi Kikuchi (菊池英一 Kikuchi Eiichi)
- Seagorath (シーゴラス Shigorasu): Toya Takanobu (遠矢孝信 Takanobu Toya)
- Seamons (シーモンス Shimonsu): Moridaira (森平 Moridaira) (with Seagroath) & Toya Takanobu (遠矢孝信 Takanobu Toya) (alone scenes)
- Return of Ultraman Vol.4 Episodes 13-16.
- Akiji Kobayashi who was playing Captain Takamura previously played Toshio Muramatsu in the Original Ultraman Series. He was now currently playing one of the main characters of Kamen Rider, Tobei Tachibana. Also, the thirteenth episode of Kamen Rider, Tokageron and the Big Monster Army aired a day after the airing of the Return of Ultraman episode.