The four Irish provinces will face each other over four weeks in the first three rounds of the Pro14 Rainbow Cup.
Ulster will host Connacht on Friday 23 April with Leinster welcoming Munster to the RDS a day later.
Rounds four to six will not be confirmed until the competition's four South Africa teams have been granted approval to travel.
The Pro14 insists that the six-round competition and final will be completed as scheduled.
The South African sides will remain at home for the opening three rounds and compete against each other.
With Ulster and Leinster in European action in the last weekend of April, the provinces will not play their second Rainbow Cup fixtures until the weekend of May 7.
Munster meet Ulster at Thomond Park with Connacht hosting Leinster.
The final weekend in inter-pros will see Leinster and Munster playing at the RDS with Munster and Connacht meeting in Limerick.
Pro14 champions Leinster are hoping to welcome back 2,000 spectators to the RDS for a Rainbow Cup fixture, having submitted a proposal to the Irish government to use the games as a rapid antigen testing pilot event.
Rainbow Cup inter-provincial fixtures
|Friday 23 April||Ulster v Connacht||Kingspan Stadium||20:15 BST|
|Saturday 24 April||Leinster v Munster||RDS Arena||19:35 BST|
|Friday 7 May||Munster v Ulster||Thomond Park||20:15 BST|
|Saturday 8 May||Connacht v Leinster||The Sportsground||19:35 BST|
|Friday 14 May||Munster v Connacht||Thomond Park||18:00 BST|
|Friday 14 May||Leinster v Ulster||RDS Arena||20:15 BST|