The former Belgium international has confirmed his decision on social media today.
“Sometimes I can't wait to retire, but on the other hand I also have a lot of ambition to continue with Antwerp," he said.
"I'll do it for another six months."
Alderweireld began his career with Ajax, where he made his debut in the 2008/09 season and played 186 games, scoring 15 goals, before moving to Atletico Madrid (22 games and two goals) and then to England, first with Southampton and then with Tottenham, where with 236 games and nine goals, he became one of Spurs' most influential players.
After leaving England, the Belgian centre-back played a season with Al-Duhail before returning to his homeland to play for Antwerp, where he has made 114 appearances and scored 13 goals.