Day lost 5–4 to Ding Junhui in the second round of the Shanghai Masters, but turned the tables at the same stage of the International Championship by beating him 6–5. Day was defeated 6–4 by David Gilbert in the following round. However, in his next event he whitewashed Mark Selby 4–0 in the quarter-finals of the Bulgarian Open and beat Sam Baird 4–2 to play in the final of an event carrying ranking points for the first time since 2008, but he was thrashed 4–0 by Mark Allen. He lost 6–2 to Dechawat Poomjaeng in the second round of the UK Championship, but knocked out reigning world champion Stuart Bingham 5–3 to reach the quarter-finals of the German Masters. Day lost the final three frames against Kyren Wilson to be eliminated 5–4.&lt;ref name="2015/16"&gt;&lt;/ref&gt; He made two centuries and won the deciding frame on the final black against John Higgins to make another quarter-final at the World Grand Prix. He was defeated 4–2 by Bingham, losing the final frame from 56–0 points up, after Bingham made a 64 break. After being defeated 10–3 by Higgins in the opening round of the World Championship, Day said he would be working on his fitness in the off season in an attempt to improve his concentration during matches.