Georgia Southern and Appalachian State announced in separate press conferences on their campuses Wednesday their athletic programs are leaving the Southern Conference to join the Sun Belt Conference in 2014.
Idaho and New Mexico State also announced Wednesday they have accepted an invitation to join the Sun Belt next year in football only.
Georgia Southern's football team has won 10 Southern Conference titles and six national championships since 1985. Appalachian State has won 10 conference titles and three national championships.
Both schools are slated to begin playing Sun Belt games and will be revenue-sharing members of the conference in 2014 and eligible for the Sun Belt conference title, but will not be eligible to play in a bowl game until 2015.
Georgia Southern President Brooks Keel called it a "milestone" day for the school.
"This decision was made with the long-term interest of our University in mind," Keel said. "The Sun Belt will provide our student athletes with an outstanding opportunity to compete at a highest level, and we are excited to contribute to the conference's success both on and off the field. I am equally excited about the opportunity that it will provide Georgia Southern and the more than 75,000 alumni that make up the Eagle Nation."
Sun Belt Conference Commissioner Karl Benson visited Georgia Southern on Wednesday morning to welcome Keel, who formally accepted the invitation.
"We have built our reputation around a focus on the student, and this move will allow us to partner to provide our student athletes with the opportunity to compete on a national stage," Georgia Southern athletic director Tom Kleinlein said.
For Georgia Southern, the move to FBS comes after 65 percent of school's students voted to pay $75 a semester to support the move.
That fee will be collected starting in the fall. Ground will also be broken in a few weeks to add 6,300 additional seats to Allen E. Paulson Stadium and build a new Football Operations Center in the east end zone.
Appalachian State joined NCAA Division I in 1970 and has been a member of the Southern Conference since 1971.
The Mountaineers have competed at the FCS level since 1982 and won an unprecedented three consecutive national championships from 2005-07.
Appalachian State's most memorable win came in 2007 when it pulled off a historic 34-32 upset over No. 5 Michigan, marking the first time that an FCS program ever toppled a nationally ranked FBS opponent.
"I am proud that Appalachian has this opportunity to compete in the Sun Belt Conference," Appalachian State Chancellor Kenneth Peacock said. "Our student-athletes have earned the opportunity to participate at this level of collegiate athletics and we welcome the new academic and athletic relationships that will develop as a result of this partnership."
The football schedule for Georgia Southern and Appalachian State for 2013 will not change. However, neither team will be eligible to win the Southern Conference championship or participate in the FCS playoffs this season.
The addition of the four new members gives the Sun Belt 12 football members in 2015. They join Arkansas State, Georgia State, Louisiana-Lafayette, Louisiana-Monroe, South Alabama, Texas State, Troy and Western Kentucky.
Arkansas-Little Rock and Texas-Arlington help make up the 12 teams participating in basketball beginning in 2014.
There are some sports teams that won't participate in the Sun Belt Conference from those schools. The Mountaineers' field hockey team will continue to compete in the NorPac Field Hockey Conference and men's soccer and wrestling will stay in the Southern Conference. Georgia Southern officials say it's unclear in which conference its men's soccer team will participate.
Idaho had been a member of the Western Athletic Conference, which has lost most of its football-playing members. The Vandals will play next season as an independent, but had been searching for a conference to join.
Idaho was a football-only member of the Sun Belt from 2001-2005 before joining the WAC. Idaho's other sports are moving to the Big Sky Conference.
New Mexico State school officials said at a campus news conference Wednesday that the move is pending approval by the state Board of Regents.
The Aggies played eight years in the WAC and will play as an independent this fall after the WAC gave up trying to field a football league in 2013.
"We were delighted to receive the official invitation and we will be proud to join," said Manuel Pacheco, New Mexico State's interim president. "This is a well-respected conference."
New Mexico State went 1-11 last season and hasn't appeared in a bowl game since 1960.