Clubs competing in the Great Eastern-YEO'S S.League are also required to participate in the S. League Reserve cum Youth Tournament, also known as the Great Eastern-YEO'S Prime League. Prime League sides also take part in the National Football League FA Cup competition.
All Prime League teams, shall register a minimum of 15 and a maximum of 20 players. Any teams not participating in the S. League shall register a minimum of 15 and a maximum of 25 players. The teams must maintain the minimum required number of players throughout the season.
Each club is allowed to register up to a maximum of two foreign players for their Prime League teams. The foreign players shall be aged eighteen and above at the point of registration but under twenty one years of age and are not eligible to play in the S.League.
An S.League player who has played in his team’s previous or last S.League match is not eligible to play in the following Prime League match or matches. Players who did not play in their team’s previous or last S.League match, as aforesaid, are not included in this category.