The Arsenal defender was forced to miss November's friendly fixtures with Japan and Norway due to injury, but she has earned an expected recall to Sarina Wiegman's squad for this month's tournament.
However, there is still no place for Williamson's former club-mate Nobbs, who ended her 13-year stay at Arsenal to join Aston Villa in January in search of more game time.
Nobbs has made three starts in the Women's Super League for Villa since her winter switch, but the 30-year-old - who left Arsenal with the intention of breaking back into the England squad - has not won Wiegman over this time.
Nobbs was included in England's squad for their November friendlies with Japan and Norway before having to withdraw through injury, and there is also no place in the ranks for Bethany England.
The former Chelsea striker left the WSL champions to sign for Tottenham Hotspur in a £250,000 deal last month, making her the most expensive WSL player of all time.
England has already netted two goals in two league games for Spurs, but she is left out alongside Nobbs, as Wiegman names a mix of youth and experience in equal measure.
The Euro 2022 champions have called up one uncapped player in the form of Everton goalkeeper Emily Ramsey, while Maya Le Tissier, Jess Park and Katie Robinson - who each have one cap apiece - are also included.
Chelsea's Fran Kirby also returns following illness, while Laura Coombs - fresh from signing a new contract with Manchester City - earns her first call-up in over two years.
Nikita Parris is another notable absentee, though, while Arsenal striker Beth Mead misses out as she recovers from a devastating ACL injury.
"The first camp of the year is always important to set the right tone for what comes next, especially with such a big opportunity in the summer," Wiegman told englandfootball.com.
"We're only looking forward now and we have to stay humble and focused on working hard. We know the fans will be with us again and we can't wait to see them at every stadium.
"We had a positive experience with the Arnold Clark Cup last time. We had three tough matches with different challenges in each one, and we were able to learn a lot from our performances and work on many details which we are aiming to do again."
England won the inaugural Arnold Clark Cup in 2022 and will be facing Italy, Belgium and South Korea in the 2023 tournament, starting with a clash against the latter in Milton Keynes on February 16.
The Lionesses will then travel to Coventry to face Italy three days later before meeting Belgium at Bristol City's Ashton Gate on February 22.
ENGLAND SQUAD IN FULL:
Goalkeepers: Mary Earps (Manchester United), Sandy MacIver (Manchester City), Emily Ramsey (Everton, loan from Manchester United), Ellie Roebuck (Manchester City)
Defenders: Millie Bright (Chelsea), Lucy Bronze (Barcelona), Jess Carter (Chelsea), Niamh Charles (Chelsea), Rachel Daly (Aston Villa), Alex Greenwood (Manchester City), Maya Le Tissier (Manchester United), Leah Williamson (Arsenal), Lotte Wubben-Moy (Arsenal)
Midfielders: Laura Coombs (Manchester City), Fran Kirby (Chelsea), Jessica Park (Everton, loan from Manchester City), Georgia Stanway (Bayern Munich), Ella Toone (Manchester United), Keira Walsh (Barcelona), Katie Zelem (Manchester United)
Forwards: Lauren Hemp (Manchester City), Lauren James (Chelsea), Chloe Kelly (Manchester City), Katie Robinson (Brighton & Hove Albion), Alessia Russo (Manchester United), Ebony Salmon (Houston Dash)