The 32-year-old last played in England on New Year's Day in 2014 and was a free agent having recently returned from a stint in the Indian Super League.
Pennant trained with Wigan last week and was in attendance at the DW Stadium on Friday night as their worrying form continued in a 3-0 loss to Charlton which leaves them deep in the relegation mire.
Wigan boss Malky Mackay has recently lost Emyr Huws and Chris Herd to season-ending injuries, while William Kvist and Leon Clarke were also forced off with problems against Charlton, meaning Pennant bolsters a squad lacking numbers.
Pennant has had a nomadic career across the divisions having also featured for the likes of Arsenal, Leeds, Birmingham and Wolves, while he also spent time in Spain with Real Zaragoza.
He played all 90 minutes in the 2007 Champions League final with Liverpool as they went down 2-1 to AC Milan in Athens.
"Jermaine needs no introduction in terms of what he has achieved in the game," Mackay told Wigan's official website.
"He's got terrific experience and is hungry for a way back into the English scene
There were a number of clubs interested, so we are delighted we can now call upon him to help us.
"He has been with us throughout the week and has trained excellently, he's brought a breath of fresh air to the place and we've been bowled over by his hunger and enthusiasm.
"Jermaine has integrated straight away into the group and I'm sure he's going to be a great addition for us."
Source : PA
Source: PA