The tournament has been designed to bridge the gap between Premiership and Pro14 competitions.
The Welsh Rugby Union (WRU) announced in March that there would be new regional sides, with players in teams mainly being aged under 23.
There will be six games before a final in September and October, with more games possible in April.
A WRU spokesperson said: "The finer details of its structure will be available shortly, but it is our collective ambition to create a new tier of professional competition for our teams that services all the requirements of a successful player pathway.
"As previously advised this competition will run alongside our existing club competitions and provide a performance environment for player development."
The Welsh Rugby Union (WRU) announced in March that there would be new regional sides, with players in teams mainly being aged under 23.
There will be six games before a final in September and October, with more games possible in April.
A WRU spokesperson said: "The finer details of its structure will be available shortly, but it is our collective ambition to create a new tier of professional competition for our teams that services all the requirements of a successful player pathway.
"As previously advised this competition will run alongside our existing club competitions and provide a performance environment for player development."
