The 20-year-old made seven appearances during a three-month loan stint at Shrewsbury Town this season.
Tranmere manager Ronnie Moore has said that Edwards will provide his side with defensive cover.
"I'm really pleased to be able to bring Ryan in," Moore told the club's official website.
"With Ash Taylor suspended and Ian Goodison carrying a groin injury we are short of options at the back. Ryan has more than 30 games of Football League experience under his belt and has done well in his previous spells out on loan so I look forward to working with him.
"I'd like to thank Blackburn manager Gary Bowyer for allowing Ryan to join us."
Edwards could make his Tranmere debut against Colchester United on Saturday.