The 2017–18 British and Irish Cup is the ninth and final season of the annual rugby union competition for second tier, semi-professional clubs from Britain and Ireland. Munster A are the defending champions having won the 2016–17 final against Jersey Reds 29–28 at Irish Independent Park, Cork on 21 April 2017. The format of the competition is similar to last season with Scottish clubs not competing. For the third consecutive season the four Welsh teams are the reserve sides of the teams competing in the Pro14 competition instead of clubs from the Welsh Premier Division.