This is the first year of the Arizona Complex League, it having previously operated as the Arizona Rookie League. Like all the minor leagues, the ARL was canceled in 2020 due to COVID-19, and as part of the wholesale re-organization of the minor leagues, it became the ACL this year. There are a total of 18 teams taking part, in three divisions of six teams apiece. The participants basically reflect the franchises who form the Cactus League (so teams on the Western side of the country), but the Giants, Brewers and Royals each have two teams taking part.
Games take place at the various spring training parks, with around a 60-game season, typically starting in late June.