The two have been aligned since 2009, with the Saints one of four Victorian clubs yet to move away from a VFL partnership.
But a redevelopment of St Kilda's former training base at Moorabbin Oval is set to have the club fielding their own team from 2016.
"The objective for both St Kilda and Sandringham to field stand-alone VFL teams from 2016 would mean that there is a clear development pathway for players of each respective club," St Kilda head of football Chris Pelchen said.
"In the meantime, our partnership continues to be an important part of St Kilda's development program and we remain committed to bringing success to Sandringham in the VFL competition."
Sandringham football club general manager John Mennie was pleased with the extension of the partnership.
"This renewed agreement will ensure that both Saints players and Sandy players are afforded the best opportunity to play at VFL level," he said.