The 2021 New Zealand National League was the first scheduled season of the National League since its restructuring in 2021. 30 clubs competed in the competition, with four having been planned to qualify from the Northern League, three qualifying from the Central League and two qualifying from the Southern League for the National Championship phase along with the automatically qualified Wellington Phoenix Reserves.Each team was allowed to field a maximum of four foreign players as well as one additional foreign player who has Oceania Football Confederation nationality. Each team had to also have at least two players aged 20 or under in the starting eleven.