Williamson missed England's matches in the second half of 2025 with a knee injury, and the 28-year-old had surgery before returning to action with Arsenal at the end of the year.
"I am very happy. It feels very good for her too, she wanted to be back," Wiegman told reporters. "She has trained, I am in close contact with her and the club. She is in a good place but she does have a lack of minutes.
"I think there are some more players who are still building or didn't get the minutes we hoped for. That is also the reason why we have gone with a bigger squad."
Goalkeeper Hannah Hampton, Jess Carter, Alex Greenwood and Lauren James are also back in the squad after missing November's internationals due to injuries, while London City Lionesses defender Poppy Pattinson has earned a first call-up.
However, Niamh Charles, Missy Bo Kearns, Ella Toone and Beth Mead are sidelined through injury. Defender Toone will be out until the end of March due to a hip problem.
"Of course you want them in the team. You know you have seen in all of the camps we have had players have lots of games, very high level," Wiegman said of Toone and Mead.
"There are always a couple of players who are injured who we can't bring in. That's part of our football life too."
England face Ukraine in Antalya, Turkey on March 3rd before hosting Iceland four days later at Nottingham Forest's City Ground. Spain are the other team in Group A3, with England facing the world champions in April at Wembley.
England squad
Goalkeepers: Hannah Hampton, Anna Moorhouse, Ellie Roebuck
Defenders: Lucy Bronze, Jess Carter, Grace Fisk, Alex Greenwood, Taylor Hinds, Maya Le Tissier, Esme Morgan, Poppy Pattinson, Leah Williamson, Lotte Wubben‑Moy
Midfielders: Laura Blindkilde Brown, Grace Clinton, Lucia Kendall, Georgia Stanway, Keira Walsh
Forwards: Aggie Beever-Jones, Freya Godfrey, Lauren Hemp, Lauren James, Chloe Kelly, Jess Park, Alessia Russo