Layden joined the Connacht academy for the 2011–12 season. Layden had previously been part of a combined Connacht/Munster side that played against a Leinster/Ulster selection in an Under-20 match to open the Aviva Stadium in 2010.[2] He was part of the Connacht team that won the Under-20 Interprovincial Championship in 2011, and scored a hat-trick of tries in the game against Munster. Layden made his senior Connacht debut on 8 October 2011, coming on in a 2011–12 Pro12 match as a replacement against Leinster.[3]
Layden's next two seasons were hampered by injuries, and although he featured for the second-tier team, the Connacht Eagles, in the British and Irish Cup, Layden did not play for the senior side again during his time in the academy. At the end of the 2013–14 season, Layden had completed the maximum three years in the academy. Despite his injury problems, Connacht offered Layden a further one-year contract, which saw him become a member of the senior team for the 2014–15 season.[4][5] Layden made three appearances in the 2014–15 Pro12, starting against Newport Gwent Dragons and Ospreys, and coming on as a replacement against Cardiff Blues.[6] Layden left Connacht at the end of the season.[7]
Layden was part of Ireland's 2017 training squad for the national sevens team.[11] Layden, however, did not earn a spot on the twelve-man roster for any of the four tournaments on the 2017 Sevens Grand Prix Series.
^"Ireland U20 centre Peter Robb one of five new recruits in Connacht academy". The Score. 24 June 2014. Archived from the original on 14 July 2014. Retrieved 12 August 2014. Fullback Shane Layden has completed his three years in the Academy, but has been re-contracted for a further season due to his injury problems during the 2013/14 campaign. The former Ireland U20 international will be part of Pat Lam's senior squad next season.
^"Carty and Finn called up to Ireland U20 World Cup squad". Westmeath Independent. 30 May 2012. Retrieved 12 August 2014. Finn replaces Buccaneers team-mate Shane Layden whose injury, unfortunately, did not recover in time to enable the exciting full-back/wing to travel.