On the men's side, all teams except Ireland and Rio 2016 host Brazil are returning to competition. That means that Belgium, Spain, Australia, New Zealand, Great Britain, Germany, the Netherlands, Argentina, India and Canada are all going to be back.

Belgium is the reigning world champion, with its star veteran players including Thomas Briels and John-John Dohmen. Challengers should include India and star Manpreet Singh, as well as Argentina and star Luca Vila.

The U.S. team, which placed fifth in 2016, is the only women's team that played in Rio and did not qualify for Tokyo. That means that the Netherlands, New Zealand, Germany, Spain, China, South Korea, Great Britain, Australia, Argentina, Japan and India are all going to be back.

Eva de Goede will return as the Netherlands looks to reclaim gold, while challengers could include New Zealand and Olivia Merry or Argentina and players like Agustina Delfina. 

Alex Danson-Bennett, a three-time Olympian and one of the stars of Great Britain's first gold medal campaign in 2016, retired in 2020 after sustaining a head trauma caused by hitting a brick wall while laughing at a joke. Danson-Bennett co-led the last two Olympic tournaments in goals. 

The men's teams from Ireland and Brazil -- which finished 10th and 12th at the 2016 Games, respectively -- will not appear in Tokyo, and neither will the U.S. women's team.

Ireland's women's team is making its Olympic debut with stars including Katie Mullan and Deirdre Duke.