2007-08 was the first since 2005 that the top division had 18 teams as a result of Neath Athletic's promotion from the Welsh Football League. This meant that all teams were in action on every matchday whereas for the previous 2 seasons there were 17 teams with one team inactive every weekend.
Cwmbran Town's relegation from the Welsh Premier League in the 2006–07 season saw them play in the First Division for 2007–08.
Barry Town, historically the most successful team in the League of Wales, suffered further relegation from the First Division to Second Division. This followed their relegation from the Welsh Premier League in 2004.