Japan at the 2015 World Aquatics Championships

Japanese divers qualified for the individual spots and the synchronized teams at the World Championships.

Men

Women

Mixed

Japan has fielded a team of four swimmers to compete in the open water marathon. Among the official roster are 2012 Olympians Yasunari Hirai and Yumi Kida.

Japanese swimmers have achieved qualifying standards in the following events (up to a maximum of 2 swimmers in each event at the A-standard entry time, and 1 at the B-standard):^[1] Swimmers must qualify at the 2015 Japanese Championships (for pool events) to confirm their places at the Worlds.

Twenty-four swimmers have been officially nominated to the Japanese team to compete in the Worlds, including defending champion Daiya Seto in the 400 m individual medley and Olympic medalists Ryosuke Irie, Ryo Tateishi, and Natsumi Hoshi.^[2] Japan's rising superstar Kosuke Hagino was set to compete, but later withdrew from the team due to elbow fracture.^[3]

Men

Athlete	Event	Heat		Semifinal		Final
		Time	Rank	Time	Rank	Time	Rank
Tsubasa Amai	200 m freestyle	1:50.04	40	Did not advance
	400 m freestyle	3:52.06	35	—N/a		Did not advance
Takuro Fujii	100 m butterfly	51.76	6 Q	51.58	9	Did not advance
Ryosuke Irie	100 m backstroke	53.37	5 Q	53.13	4 Q	53.10	6
	200 m backstroke	1:56.68	2 Q	1:55.76	5 Q	1:54.81	4
Masaki Kaneko	50 m backstroke	25.49	23	Did not advance
	100 m backstroke	54.19	17	Did not advance
	200 m backstroke	1:57.63	9 Q	1:57.33	10	Did not advance
Takeshi Kawamoto	50 m butterfly	23.61	13 Q	23.74	16	Did not advance
	100 m butterfly	52.41	21	Did not advance
Yuki Kobori	200 m freestyle	1:48.09	18	Did not advance
Yasuhiro Koseki	50 m breaststroke	28.13	30	Did not advance
	100 m breaststroke	59.93	10 Q	1:00.31	14	Did not advance
	200 m breaststroke	2:10.47	13 Q	2:08.03	1 Q	2:09.12	5
Katsumi Nakamura	50 m freestyle	22.25	10 Q	22.15	13	Did not advance
	100 m freestyle	49.07	19	Did not advance
Masato Sakai	200 m butterfly	1:55.97	7 Q	1:54.75	3 Q	1:54.24	4
Daiya Seto	200 m butterfly	1:55.60	3 Q	1:54.95	5 Q	1:55.15	6
	200 m individual medley	1:59.11	7 Q	2:00.05	14	Did not advance
	400 m individual medley	4:12.17	3 Q	—N/a		4:08.50
Shinri Shioura	50 m freestyle	22.34	12 Q	22.08	11	Did not advance
	100 m freestyle	48.84	14 Q	48.96	15	Did not advance
Ryo Tateishi	100 m breaststroke	1:01.26	29	Did not advance
	200 m breaststroke	2:13.23	25	Did not advance
Katsumi Nakamura Shinri Shioura Yuki Kobori Takuro Fujii	4×100 m freestyle relay	3:14.76	5 Q	—N/a		3:15.04	6
Yuki Kobori Tsubasa Amai Naito Ehara Daiya Seto	4×200 m freestyle relay	7:11.59	10	—N/a		Did not advance
Takuro Fujii Ryosuke Irie Yasuhiro Koseki Shinri Shioura	4×100 m medley relay	3:32.82	4 Q	—N/a		3:31.10	6

Women

Athlete	Event	Heat		Semifinal		Final
		Time	Rank	Time	Rank	Time	Rank
Sayaka Akase	100 m backstroke	1:01.62	=29	Did not advance
Natsumi Hoshi	100 m butterfly	58.47	15 Q	58.45	14	Did not advance
	200 m butterfly	2:07.97	5 Q	2:06.36	1 Q	2:05.56
Chihiro Igarashi	200 m freestyle	1:58.31	=13 Q	1:57.75	11	Did not advance
	400 m freestyle	4:13.43	20	—N/a		Did not advance
	400 m individual medley	4:43.06	16	—N/a		Did not advance
Rikako Ikee	50 m butterfly	26.66	19	Did not advance
Rie Kaneto	50 m breaststroke	31.99	31	Did not advance
	100 m breaststroke	1:07.71	18	Did not advance
	200 m breaststroke	2:25.75	15 Q	2:22.88	6 Q	2:23.19	6
Yayoi Matsumoto	50 m freestyle	25.90	38	Did not advance
	100 m freestyle	55.71	32	Did not advance
Sachi Mochida	200 m freestyle	1:59.35	20	Did not advance
Sakiko Shimizu	200 m individual medley	2:12.27	8 Q	2:11.53	10	Did not advance
	400 m individual medley	4:36.16	6 Q	—N/a		4:37.19	6
Miki Uchida	50 m freestyle	25.33	22	Did not advance
	100 m freestyle	54.22	=10 Q	54.30	12	Did not advance
Kanako Watanabe	100 m breaststroke	1:06.81	5 Q	1:06.64	5 Q	1:06.43	4
	200 m breaststroke	2:23.29	1 Q	2:22.15	3 Q	2:21.15
	200 m individual medley	2:10.37	3 Q	2:09.61	3 Q	2:08.45
Misaki Yamaguchi	50 m butterfly	26.68	20	Did not advance
Miki Uchida Rikako Ikee Misaki Yamaguchi Yayoi Matsumoto	4×100 m freestyle relay	3:38.47	9	—N/a		Did not advance
Chihiro Igarashi Rikako Ikee Sachi Mochida Tomomi Aoki	4×200 m freestyle relay	7:54.58	6 Q	—N/a		7:54.62	7
Sayaka Akase Natsumi Hoshi Miki Uchida Kanako Watanabe	4×100 m medley relay	4:00.43	8 Q	—N/a		DSQ

Mixed

Japan fielded a full squad of twelve synchronized swimmers (one male and eleven female) to compete in each of the following events.

Women

Athlete	Event	Preliminaries		Final
		Points	Rank	Points	Rank
Yukiko Inui	Solo technical routine	89.5851	5 Q	90.7603	5
	Solo free routine	91.7333	5 Q	92.4333	5
Yukiko Inui Risako Mitsui	Duet technical routine	90.3504	3 Q	92.0079
	Duet free routine	93.5333	3 Q	93.4333	4
Aika Hakoyama Yukiko Inui Kei Marumo Risako Mitsui Kanami Nakamaki Mai Nakamura Kano Omata Kurumi Yoshida	Team technical routine	91.6516	4 Q	92.4133
Aika Hakoyama Aiko Hayashi Yukiko Inui Kei Marumo Risako Mitsui Kanami Nakamaki Mai Nakamura Kurumi Yoshida	Team free routine	93.7000	3 Q	93.9000
Aika Hakoyama Aiko Hayashi Yukiko Inui Kei Marumo Risako Mitsui Kanami Nakamaki Mai Nakamura Kano Omata Asuka Tasaki Kurumi Yoshida	Free routine combination	92.6000	3 Q	93.8000

Mixed