[1][2] The English county teams (London, Warwickshire and Lancashire) did not compete due to the COVID-19 pandemic travel restrictions.
[3][4] In February 2021 it was announced that the league would be delayed due to the impact of the COVID-19 pandemic on Gaelic games and that cancelling it would be a last resort.
London, Lancashire and Warwickshire did not take part; they retained their division placings (2B, 3A and 3B respectively) for the 2022 National Hurling League.
The top team in each group will be deemed "Co-champion", unless they are drawn together in the 2021 All-Ireland Senior Hurling Championship, in which case the match will double up as the league final.
If the two teams that won Divisions 1A and 1B (Galway and Kilkenny respectively) had met in the 2021 All-Ireland Senior Hurling Championship, this would have doubled as the league final.