As a result of the modified, COVID-affected 2020 season, three of the top four teams in 2019 (Wellington Saints, Hawke's Bay Hawks and Southland Sharks) did not compete.
All three teams re-entered in 2021 to increase the league's total number to 10 for the first time since 2014.
[2] The Saints won their 12th NBL championship in 2021 with a win over the Hawks in the grand final.
In the final round of the regular season, due to an extreme weather event and major flooding across the top of the South Island, the games between the Manawatu Jets and Nelson Giants (Sunday 5pm) and Taranaki Mountainairs and Nelson Giants (Monday 7:30pm) were both cancelled.
With the games not having an impact on the 2021 Final Four, the League advised neither clash would be rescheduled.