The number of substitutes, up to a maximum of five, which may be used in any match played in an official competition will be determined by FIFA, the confederation or the national football association. except For men's and women's competitions involving the 1st teams of clubs in the top division or senior ‘A’ international teams where the maximum is three substitutes competition rules permit a maximum of five substitutes to be used, each team:
*Where both teams make a substitution at the same time, this will count as a used substitution opportunity for both teams. Multiple substitutions (and requests) by a team during the same stoppage in play count as one used substitution opportunity.
If a team has not used the maximum number of substitutes and/or substitution opportunities, any unused substitutes and substitution opportunities may be used in extra time
Where competition rules permit teams to use one additional substitute in extra time, each team will have one additional substitution opportunity
Substitutions may also be made in the period between full-time and the start of extra time, and at half-time in extra time – these do not count as used substitution opportunities.
The competition rules must state:
how many substitutes may be named, from three to a maximum of twelve fifteen
whether one additional substitute may be used when a match goes into extra time (whether or not the team has already used the full number of permitted substitutes)
In national senior 'A' international team matches, a maximum of twelve fifteen substitutes may be named of which a maximum of six may be used.
In all other matches, a greater number of substitutes may be used provided that:
If the referee is not informed, or if no agreement is reached before the match, each team is allowed a maximum of six substitutes.
The use of return substitutions is only permitted in youth, veterans, disability and grassroots football, subject to the agreement of the national football association, confederation or FIFA.