Hay mainly competed in British Milers Club meetings in 2013, although he did manage sixth in the 5000 m at that year's British Athletics Championships as well as twelfth place and team gold in the under-23 section of the 2013 European Cross Country Championships. He struggled to transition into the senior ranks on the track the following year, coming 15th nationally in the 5000 m despite winning the British under-23 title. He placed within the top ten at the Great North Run. He returned to the European Under-23 Cross Country race and managed fourth place – Britain's best performer – and led the British to the team silver medals behind Russia.