The opening match in Group F pits many people's favourites for the competition - Japan - against a pacey Canada outfit in Cardiff.
Japan eliminated Germany at the quarter-final stage of the Women's World Cup last year, and therefore will enter the tournament full of confidence.
All 14 of Japan's squad from last year's final are part of their Olympic team, although they do enter the match with skipper and World Cup Golden Ball winner Homare Sawa a possible injury doubt.
Meanwhile, Canada finished last at the 2011 World Cup, but did look a much-improved outfit when they lost narrowly to the United States in June.
The Canadians' main threat comes in the shape of Christine Sinclair, who is many people's outside bet for the top scorer in the tournament.
Possible starting lineups:
Japan: Kaihori; Yukari, Iwashimizu, Sameshima, Kumagai; Homare, Miyama, Ando, Sakaguchi, Sawa; Ohno
Canada: McLeod; Moscato, Timko, Filigno, Zurrer; Wilkinson, Matheson, Chapman, Schmidt, Kyle; Sinclair
Sports Mole says: 3-0
