Fly-half Umaga and flanker Willis are rewarded after impressing for Wasps this season, while there is also a place for club colleague Dan Robson.
The trio all started Saturday's Premiership final but were unable to help Wasps triumph at Twickenham, Exeter Chiefs instead crowned domestic champions for the 2019-2020 season.
Joe Simmonds was influential for Exeter in the 19-13 victory, kicking a conversion and four penalties, but he has not been selected. There is no place for his brother, Sam, either.
Jack Nowell is one of several notable names absent due to injury. Elliot Daly, George Ford and Joe Marler are also missing, along with long-term absentees Courtney Lawes and Manu Tuilagi.
However, Jones made clear he still had to make some difficult calls when putting together the final list for Saturday’s rescheduled Six Nations clash with Italy, as well as the upcoming autumn internationals.
There are nine players yet to feature at international level on the final list.
"It was a tough squad to pick and I know there are a number of disappointed players that have just missed out," Jones said. "We've got a good balance between experience and inexperience.
"With nine players out injured, it does create some opportunities for the younger guys to show what they can do."
England still have a chance of winning the Six Nations as they complete their fixtures against Italy, the tournament having been halted earlier in the year due to the coronavirus pandemic.
They were due to face the Barbarians in a warm-up fixture beforehand, but that was cancelled due to breaches of the COVID-19 code of conduct.
After the game with Italy, England face Georgia, Ireland and Wales as part of the Autumn Nations Cup, while there will also be a play-off Test against a nation from Group B to follow.
Backs: Joe Cokanasiga, Owen Farrell, George Furbank, Willi Heinz, Jonathan Joseph, Ollie Lawrence, Max Malins, Joe Marchant, Jonny May, Dan Robson, Henry Slade, Ollie Thorley, Jacob Umaga, Anthony Watson, Ben Youngs.
Forwards: Tom Curry, Tom Dunn, Ben Earl, Charlie Ewels, Ellis Genge, Jamie George, Jonny Hill, Ted Hill, Maro Itoje, Joe Launchbury, Lewis Ludlam, Beno Obano, David Ribbans, Jack Singleton, Kyle Sinckler, Will Stuart, Sam Underhill, Billy Vunipola, Mako Vunipola, Harry Williams, Jack Willis.