Ospreys will host Cardiff Blues in the first Rainbow Cup Welsh derby on Saturday, 24 April with Scarlets at Dragons the following day.
There are doubts over the involvement of South Africa's four teams, but three fixture rounds have been confirmed.
Sharks chief Eduard Coetzee has said the Pro14's new tournament is in danger of being cancelled because of Covid-19.
The four South African teams are reported to have been told they will not be allowed to travel to the UK.
Pro14's statement detailing the first three rounds appears confident the full tournament will be played.
The statement detailing the fixtures said: "Confirmation for Rounds 4-6 will follow once Pro14 Rugby has received all necessary approvals and permissions from the relevant governments and health authorities for the South African teams to travel."
The tournament is a precursor to South Africa's leading four teams expanding the Pro14 to 16 sides in 2021-22.
It will also give Springboks hopefuls the chance to impress before they take on the British and Irish Lions in the summer with South Africa not having played since winning the 2019 World Cup because of the coronavirus pandemic.
The 2020-21 Pro14 tournament was also curtailed to usher in the South African teams via the Rainbow Cup.
Welsh regions' Rainbow Cup derbies, rounds 1-3
Saturday, 24 April
Ospreys v Cardiff Blues, 17:15 BST
Sunday, 25 April
Dragons v Scarlets, 13:00 BST
Saturday, 8 May
Scarlets v Ospreys, 19:35 BST
Sunday, 9 May
Cardiff Blues v Dragons, 13:00 BST
*Sunday, 16 May
Dragons v Ospreys, 13:00 BST
*Scarlets v Cardiff Blues, TBC 15/16 May