Marshall, Old Dominion and Southern Miss all will terminate their membership with Conference USA on June 30, the schools announced Friday.
The three schools, which are bound for the Sun Belt, said in similar statements that they first communicated their intent in December to cease participation in Conference USA at the end of the 2021-22 academic year.
All three schools say Conference USA has been unwilling to discuss a resolution for the June departures. On Jan. 20, Conference USA said in a statement that the three departing members were expected to follow league bylaws and honor their contracts by remaining through the 2022-23 academic year.
According to Extra Points, Conference USA bylaws state that members must give the conference 14 months' notice before departing. Marshall, Old Dominion and Southern Miss announced their departures to the Sun Belt in October.
"There is major realignment happening across the collegiate athletics landscape. All conferences and their members have agreed upon bylaws and contractual obligations for when transition occurs," Conference USA said in a statement Friday. "We have chosen not to engage publicly, but have communicated with our member institutions and expect them to meet those obligations."
The three schools say they are publicly expressing their intent to terminate Conference USA membership in June so that the league's remaining members can have assurances about their 2022 schedules. Conference USA releases schedules for fall sports, including football, around March 1, and has been including Marshall, Old Dominion and Southern Miss in its plans.
"The University offered to cooperate with the conference to ensure that all remaining C-USA members had complete competitive schedules for those sports in which the university competes," Old Dominion's statement reads. "The Conference refuses to discuss such an arrangement with the university. The remaining members of Conference USA deserve certainty about their schedules as they plan for competition next year. For their sake, the university makes public its intent."
Conference USA was set to release its 2022 schedule including the three departing members, as a way to leverage them into staying, a source told ESPN.
"It's not going to be an amicable split," the source said. "It's gotten ugly, and I assume it's going to get uglier."
The three outgoing member schools' announced early departures are not expected to impact their participation in upcoming postseason league tournaments for winter and spring sports, the conference told ESPN.
Six other schools -- UTSA, Florida Atlantic, North Texas, Rice, UAB and Charlotte -- are set to leave Conference USA for the American Athletic Conference, and will begin play in the fall of 2023. Conference USA is set to add four new members -- Liberty, New Mexico State, Sam Houston State and Jacksonville State -- in 2023.
The Sun Belt also is adding James Madison, an FCS program, which will begin its membership on July 1. The Colonial Athletic Association prohibited James Madison teams from participating in its league tournaments after the school announced its departure.