Connacht will be reacquainted with former head coach Pat Lam in the group stage of this season's Heineken Champions Cup.
They've been drawn to play Lam's Bristol Bears and last season's runners-up Racing in the pool stage.
Leinster will play Montpellier and Northampton.
Munster face games against Clermont and Harlequins.
While Ulster will go up against Gloucester and Toulouse.
All four provinces face home and away games against each of their opponents, with the first round of matches coming in mid-December.