Southgate has a week before he has to trim his squad to 26 for the finals which start on June 11.
The England boss will hope to avoid any injuries, with 12 of the provisional squad involved in European finals this week.
Manchester United take on Villarreal for the Europa League on Wednesday before Manchester City and Chelsea face off in an all-English Champions League final on Saturday.
United and Liverpool captains Harry Maguire and Jordan Henderson as well as Leeds midfielder Kalvin Phillips are all included in Southgate’s squad despite injury doubts.
Liverpool’s Trent Alexander-Arnold is among four right-backs amid speculation he is set to miss out on the final squad despite a return to form in the final weeks of the season.
England face Austria on June 2 and Romania four days later in pre-tournament friendlies at Middlesbrough’s Riverside Stadium.
The Three Lions begin their Euro 2020 campaign against Croatia on June 13 before facing Scotland and the Czech Republic in Group D.
Provisional England squad in full:
Goalkeepers: Jordan Pickford (Everton), Dean Henderson (Manchester United), Sam Johnstone (West Brom), Aaron Ramsdale (Sheffield United)
Defenders: Luke Shaw, Harry Maguire (Manchester United), Ben Chilwell, Reece James (Chelsea), John Stones, Kyle Walker (Manchester City), Tyrone Mings (Aston Villa), Conor Coady (Wolves) Kieran Trippier (Atletico Madrid/ESP), Trent Alexander-Arnold (Liverpool), Ben Godfrey (Everton), Ben White (Brighton)
Midfielders: Declan Rice, Jesse Lingard (West Ham), Jordan Henderson (Liverpool), Kalvin Phillips (Leeds), Mason Mount (Chelsea), Jude Bellingham (Borussia Dortmund/GER), James Ward-Prowse (Southampton)
Forwards: Phil Foden, Raheem Sterling (Manchester City), Jack Grealish (Aston Villa), Harry Kane (Tottenham), Marcus Rashford, Mason Greenwood (Manchester United), Jadon Sancho (Borussia Dortmund/GER), Dominic Calvert-Lewin (Everton), Bukayo Saka (Arsenal), Ollie Watkins (Aston Villa). (AFP)