The 26-year-old has become the Latics' second signing of the January transfer window so far, signing a two-and-a-half-year deal that ends a four-year stint in the MLS
The Honduras international makes the move after four years and 113 games in the MLS and is eligible to play in Saturday’s FA Cup third round tie against AFC Bournemouth.
The 26-year-old's move has been in the pipeline for a long time and he told Goal.com in December that he was looking forward to the challenge of the Premier League and ready to "give his all" for Roberto Martinez.
“I am just so happy to finally be here,” Espinoza told Wigan’s official site.
“It’s taken a while to get all the paper work done but now I can concentrate on fighting for my place and helping the team.
“I just want to say a big thank you to everyone at the club who have been working so hard to get everything through in time, and for the manager to have the belief in me. Now it’s down to business.”
Martinez was similarly pleased in concluding his second signing of the current window, suggesting Espinoza will add “something new” to his side and citing the example of the midfielder’s performances during the Olympics as proof of his talent.
“It is great to finally welcome Roger to Wigan and I know the supporters will give him a real Latics welcome,” said Martinez.
“Usually players would have more time preparing for their debut and getting used to their new team-mates, but Roger is so desperate to play as soon as he can that we hope to see him on the pitch on Saturday.
“He is an excellent talent and every time we have seen him play he has shown the desire that as a club we like to see from our players.
“The Olympics in the summer gave a great example of just what he can do on the pitch, especially in his performances against Spain and Brazil.
“He’ll bring something new to the group and we hope to have many happy memories of him playing for Latics.”