The 31-year-old left St Mary’s for the London club in a £30 million move following Southampton’s relegation to the Championship in 2023.
Ward-Prowse made 410 appearances for the Saints, scoring 55 goals and becoming renowned for his exceptional free-kick ability. He has now rejoined the Hampshire club as they attempt to win promotion back to the Premier League this season.
Speaking after completing his return, the midfielder admitted that being back in Southampton colours felt strangely familiar.
“It feels a bit surreal," he said. "The last couple of days have been pretty intense, but I’m delighted to be back, and to be wearing the red and white again is truly special.
“It’s the place I call home, obviously having come through the academy since I was eight. It was an incredible journey up until the point that I left, but home is a special place and I always had it in the back of my mind that it was somewhere that I wanted to be.
"I’m here today very excited and looking forward to the challenge ahead.”
Ward-Prowse had one year remaining on his contract at West Ham, with reports suggesting Southampton paid only £1m to bring him back to the south coast.
He joins Flynn Downes, Caspar Jander and Cam Bragg in a potentially formidable midfield under manager Tonda Eckert.
Southampton will be hoping Ward-Prowse can help transform their fortunes after a difficult start to the Championship campaign, with the club currently bottom of the table on negative points following the fallout from the major 'Spygate' scandal.
