Almost half of the players selected on Tuesday play in leagues outside Japan, mainly England, Sweden and the United States.
Japan are hoping to rebound after being knocked out in the Round of 16 in 2019. The Japanese were runners-up in 2015 and won the title in 2011.
"We will fight for the top spot with great ambition," Ikeda said, speaking in Japanese.
"But the level of (women's) football in the world is improving very rapidly."
Yui Hasegawa of Manchester City heads the list from overseas along with accomplished midfielder Fuka Nagano of Liverpool.
The youngest player on the squad is 19-year-old Maika Hamano, who plays on loan from Chelsea with Swedish club Hammarby.
The best known of the Japanese players based in the US is Angel City's forward Jun Endo.
The major absence is Mana Iwabuchi, who played in three straight World Cups. The 30-year-old has been playing at Tottenham on loan from north London rivals Arsenal.
"I have chosen (players) not for any one reason, but for their performance in the national team, their condition, their situation in the team and their performance in various competitions," Ikeda said.
Japan plays their three Group C games in New Zealand, opening with Zambia in Hamilton on July 22 before facing Costa Rica on July 26 in Dunedin and Spain in Wellington on July 31.
The Women's World Cup is being co-hosted by Australia and New Zealand.
JAPAN'S 26-PLAYER WORLD CUP SQUAD:
Goalkeepers: Ayaka Yamashita, Momoko Tanaka, Chika Hirao
Defenders: Risa Shimizu, Moeka Minami, Saki Kumagai, Shiori Miyake, Kiko Seike, Miyabi Moriya, Rion Ishikawa
Midfielders: Fuka Nagano, Hinata Miyazawa, Hikaru Naomoto, Jun Endo, Yui Hasegawa, Hina Sugita, Honoka Hayashi, Aoba Fujino, Hana Takahashi
Forwards: Riko Ueki, Mina Tanaka, Maika Hamano, Remina Chiba.
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