The agreement will see the sale of a minimum of 300 seats every match to visiting supporters for €30.
The Primera División teams backed the agreement proposed by supporters’ group Aficiones Unidas (United Support), matching the one that already existed in the second-tier Segunda División.
LaLiga noted that Athletic Club, Real Betis, Sevilla FC, Valencia CF and Real Valladolid laid the foundations for the agreement, which was made official on July 6.
RC Celta president Carlos Mouriño said: “This agreement fits perfectly with one of our objectives, to give our fans all the possible facilities in their movements, and in this case also to the followers of our rivals.
“It is therefore beneficial for everyone and that is why we are happy to join an initiative that will allow fans of the LaLiga teams to enjoy advantageous conditions on most of the fields.”