McManus would lose in the first round of the UK Championship to Joel Walker. He won his first qualifier for the 2015 German Masters against Zak Surety but was then defeated in the final qualifying round by Matthew Selt. McManus had a good run in the Welsh Open, reaching the last 16 before losing to Maguire. He performed well in the season's European Tour Events, finishing 18th on the Order of Merit. He played in four of the six events, reaching one quarter-final with a further three last 16 appearances. This gave him entry into the Grand Final where he was defeated 1–4 by Bingham in the first round. McManus won all three of his World Championship qualifying matches, defeating Michael Wasley, Andrew Pagett and Mitchell Mann to reach the main draw at the Crucible. However, an inconsistent performance against Ali Carter saw McManus bow out 5–10 in the first round.