2008-09: Hannay played his second season for the Moncton Flyers in New Brunswick. In 42 games, including playoffs, he scored 7 goals with 21 assists and 110 PMs.
2009-10: Hannay skated in 54 games for the QMJHL's Halifax Mooseheads in his first season of major junior hockey. Playing for the league's worst team (Halifax won 13 games), he was -17 and scored 1 goal with 5 assists. Hannay was second on Halifax with 158 PMs, including 16 fighting majors. Not among the 210 North American skaters in Central Scouting's final rankings, Hannay was selected by Vancouver in the seventh round (205th overall) of the 2010 NHL Draft.
2010-11: Hannay led Halifax in penalty minutes in his second QMJHL season and played primarily a shut-down defense-first role for the Mooseheads. He was -12 and had 7 assists with 164 PMs in 58 games on a Halifax team that was again in the bottom of the league standings (winning 20 games). Despite their record, the Mooseheads reached the QMJHL playoffs and were swept by Montreal. In four playoff games Hannay had 1 assist and was -2 with 13 PMs.