depends what league you play for the older usually 11 but younger sometimes 8-9
11are ne at once
For adult soccer there are 11 players on the field, plus a number of substitutes as allowed by the competition you are playing in. Unlike American football once a player has been substituted...
11 players can play on a field at a time. The MLS roster has 20 players.11
11 on field I believe each team can have up to 26 on their regular season roster.