Saints' Under 21 side will kick off the inaugural Barclays U21 Premier League campaign at home to Sunderland.
Martin Hunter's men have been placed into National Group 2 of the newly-created competition along with seven other sides, including the Black Cats.
Also included in Group 2 are Aston Villa, Manchester United, Newcastle United, Stoke City, Tottenham Hotspur and Watford.
Teams will play each-other once at home and once away during the National Group stage, before progressing further into the competition depending on their performance in the first part of the season.
U21 matches will generally take place at any time between Friday to Monday, with Saints keen to ensure as many of their fixtures take place on Monday so players can be involved with the First Team if required.
Clubs must play at least two of their seven home fixtures at their main stadium, with Saints agreeing to hold matches against Tottenham, Newcastle and Manchester United at St Mary's.
Home fixtures will otherwise take place behind closed doors at the Club's Staplewood Training Ground in Marchwood.
Saints' Barclays U21 Premier League National Group fixtures are as follows:
Monday 20th August (2pm) – Southampton v Sunderland at Staplewood
Monday 27th August (1pm) – Newcastle United v Southampton at Northumberland FA
Monday 3rd September (2.30pm) – Southampton v Aston Villa at Staplewood
Monday 17th September (7pm) – Watford v Southampton (venue to be confirmed)
Monday 24th September (7pm) – Southampton v Tottenham Hotspur at St Mary's
Monday 1st October (2.30pm) – Southampton v Stoke City at Staplewood
Monday 8th October (7pm) – Manchester United v Southampton at Altrincham FC
Saturday 20th October (tbc) – Aston Villa v Southampton (venue to be confirmed)
Monday 29th October (7pm) – Southampton v Newcastle United at St Mary's
Monday 5th November (7pm) – Sunderland v Southampton (venue to be confirmed)
Monday 12th November (2pm) – Tottenham Hotspur v Southampton (venue to be confirmed)
Monday 19th November (2.30pm) – Southampton v Watford at Staplewood
Saturday 24th November (11am) – Stoke City v Southampton (venue to be confirmed)
Monday 3rd December (7pm) – Southampton v Manchester United at St Mary's