These playoffs determined the Eastern Canadian representative in the 1991 Allan Cup final.
Champions[]
- Nova Scotia: Dartmouth Mounties
- Prince Edward Island: Charlottetown Islanders
- Ottawa District: Cardinal Red Wings
- Quebec: Laval Lunasso
Semi-Finals[]
Best of 5
- Laval 11 Cardinal 3
- Laval 6 Cardinal 3
- Laval 13 Cardinal 1
Laval Lunasso beat Cardinal Red Wings 3 games to none.
Best of 7
- Charlottetown beat Dartmouth
- Dartmouth 3 Charlottetown 0
- Charlottetown 7 Dartmouth 1
- Dartmouth 5 Charlottetown 3
- Dartmouth 6 Charlottetown 4
- Charlottetown 4 Dartmouth 2
- Charlottetown 4 Dartmouth 1
Charlottetown Islanders beat Dartmouth Mounties 4 wins to 3.
Final[]
Best of 7
- Charlottetown 6 Laval 3
- Laval 3 Charlottetown 2 (2OT)
- Charlottetown 4 Laval 2
- Charlottetown 4 Laval 3 (2OT)
- Charlottetown 6 Laval 2
Charlottetown Islanders beat Laval Lunasso 4 wins to 1.
Charlottetown Islanders advanced to the 1991 Allan Cup Final.