Lumiere was ridden in all of her 2015 races by William Buick. She made her racecourse debut in a maiden race over six furlongs at Newmarket Racecourse on 9 July and started the 6/5 favourite against seven opponents. She led from the start, accelerated away from the field approaching the final furlong and won impressively by six lengths from Sharja Queen. The filly was then moved up sharply in class for the Group 2 Lowther Stakes at York Racecourse on 20 August and started the 9/4 favourite ahead of the Princess Margaret Stakes winner Besharah. She took the lead soon after the start but was overtaken by Besharah inside the final furlong and was beaten two and a quarter lengths into second place. On her third and final appearance as a juvenile, Lumiere was one of eight fillies to contest the Group One Cheveley Park Stakes over six furlongs at Newmarket on 26 September and started the 100/30 third choice in the betting behind Besharah and the Duchess of Cambridge Stakes winner Illuminate. A two-horse Irish challenge comprised Alice Springs and the Curragh Stakes winner Bear Cheek. Lumiere took the lead from the start and opened up a clear advantage at half way. She was strongly challenged in the closing stages but stayed on to win by half a length, a head and three quarters of a length from Illuminate, Besharah and Alice Springs. After the race Johnston said "We always thought there was no shortage of stamina but we also know she's very fast and has a tremendous cruising speed. I'm very, very hopeful she can stay a mile".
2016: three-year-old season
Lumiere began her second season in the 1000 Guineas at Newmarket on 1 May and started the second favourite in a sixteen-runner field. After starting strongly and disputing the early lead she dropped away quickly in the last three furlongs and finished last behind Minding. After a two month break the filly was dropped in class for her return in the Listed Sir Henry Cecil Stakes at Newmarket on 7 July. Ridden as in the Guineas by Joe Fanning she started 3/1 favourite and posted a decisive win as she took the lead approaching the last quarter mile and drew away to win "comfortably" by six lengths from the colt Cymric. Later that month she was sent to France for the Group 1 Prix Rothschild over 1600 metres at Deauville Racecourse in which she briefly held the lead 500 metres out before fading to finish ninth behind Qemah. James Doyle partnered Lumiere in her last two races. She was dropped in distance for the Group 3 Sceptre Stakes over seven furlongs at Doncaster Racecourse on 9 September and finished third to Spangled and Mise En Rose after leading inside the final furlong. I the Challenge Stakes on 7 October over the same distance at Newmarket she led for most of the way before being overtaken in the closing stages and beaten a length by the colt Aclaim.
