On 19 May 2017, it was announced that Ryan would be leaving Munster upon the conclusion on the 2016–17 season to join French Top 14 side Racing 92. A neck hernia ruled Ryan out until the end of November 2017, though he made his Racing debut on 3 December 2017 and started against his former club Munster on 14 January 2018. Ryan featured as a replacement for Racing 92 in the 2020 European Rugby Champions Cup Final against English club Exeter Chiefs on 17 October, which the Parisian side narrowly lost 31–27. Ryan's final game for Racing 92 was their 19–6 defeat against Ronan O'Gara's La Rochelle in the semi-finals of the 2020–21 Top 14 season on 18 June 2021.