The format of the competition began with a play-off qualification round at the end of the preceding season featuring teams from England, France, Ireland and Wales.

Twenty clubs from the three major European domestic and regional leagues competed in the Champions Cup.

[4] Semi-finals Play-off final Below is the list of coaches, captain and stadiums with their method of qualification for each team.

Note: Placing shown in brackets, denotes standing at the end of the regular season for their respective leagues, with their end of season positioning shown through CH for Champions, RU for Runner-up, SF for losing Semi-finalist and QF for losing Quarter-finalist.

[5][13] Teams in the same pool play each other twice, at home and away, in the group stage that begins on the weekend of 13/14/15 October 2017, and continues through to 19/20/21 January 2018.

[14] In the event of a tie between two or more teams, the following tie-breakers will be used, as directed by EPCR: The eight qualifiers were ranked according to their performance in the pool stage and competed in the quarter-finals which were held on the weekend of 30/31 March, 1 April 2018.

In lieu of the draw that used to determine the semi-final pairing, EPCR announced that a fixed semi-final bracket would be set in advance, and that the home team would be designated based on "performances by clubs during the pool stages as well as the achievement of a winning a quarter-final match away from home".