Results for Japan in 400 metres Freestyle, Women

Olympic and Intercalated results only.

Games	Athlete/Team	Placement
1932 Summer Olympics	Hatsuko Morioka	11
1936 Summer Olympics	Kazue Kojima	6
	Hatsuko Morioka	11
1952 Summer Olympics	Sadako Yamashita	28
	Misako Tamura	33
1956 Summer Olympics	Eiko Wada	20
	Yukiko Otaka	22
1960 Summer Olympics	Kimiko Ezaka	=21
	Eiko Wada	=21
1964 Summer Olympics	Kazue Hayakawa	11
	Tazuko Kikutani	22
1984 Summer Olympics	Chikako Nakamori	14
	Junko Sakurai	19
1988 Summer Olympics	Chikako Nakamori	15
	Tomomi Hosoda	19
1992 Summer Olympics	Suzu Chiba	8
1996 Summer Olympics	Eri Yamanoi	7
	Suzu Chiba	13
2000 Summer Olympics	Sachiko Yamada	12
	Yasuko Tajima	23
2004 Summer Olympics	Ai Shibata	5
	Sachiko Yamada	6
2008 Summer Olympics	Ai Shibata	31
2012 Summer Olympics	Aya Takano	26
2016 Summer Olympics	Chihiro Igarashi	12
2020 Summer Olympics	Waka Kobori	11
	Miyu Namba	20
2024 Summer Olympics	Waka Kobori	11