When Wigan Athletic were formed in 1931 they started off wearing red and white halves, which is the same colour as the perhaps more famous Rugby League club.
They didn't start wearing their more familiar blue and white strip until 1947. The reason for the change in colour being that there was a clothing shortage on at the time and the kit suppliers could only manage to provide them with blue and white.
Since then they have always worn some combination of blue and white, with a special kit being manufactured in 1973 for their appearance in the FA Trophy final. At the time Wigan were in the Northern Premier League and unfortunately for them they went down 2-1 to Scarborough.
One exception to them wearing blue and white came when they introduced a blue and black kit for the 1993 - 1994 season.
In 1995 with Wigan close to bankrupcy Dave Whelan of JJB sports fame took control of the club and they started their climb up the divisions. He did start to make some changes to the kit too, as the blue colour was altered slightly and green was added to match the company colours.
In 2004 Whelan stopped his involvement in JJB and Wigan went back to their original blue and got rid of the green.
Here's their current kit at the time of writing.
For more information on the club history: