The Three Lions boss will have to make significant cuts to his selection by the June 7 deadline, at which point teams must submit a squad of at least 23 and up to 26 players for the Championships.
England's Euro 2024 campaign will commence on June 16 with a tie against Group C rivals Serbia, before Denmark and Slovenia await on June 20 and June 25 respectively.
Prior to the Euros, Southgate's side have two friendlies pencilled in for the start of June, as the Three Lions will take on Bosnia and Herzegovina at St James' Park on June 3, four days before Iceland stop over at Wembley.
As many as seven and up to 10 players will be axed from the ranks over the next couple of weeks, and Southgate has named a troupe brimming with both experience and youthful talent, with a few notable omissions.
Adam Wharton, Kobbie Mainoo among young players included
Aaron Ramsdale's lack of Arsenal minutes have not impacted his standing as Jordan Pickford's number two, while Dean Henderson benefits from an injury to Crystal Palace teammate Sam Johnstone to make the cut as well.
Despite Jack Butland's impressive performances for Rangers, Burnley's James Trafford - who lost his place in the Clarets lineup towards the end of the season - is selected as Southgate's fourth preliminary goalkeeper but will likely be one of the players sacrificed for the actual tournament.
Defensive stalwarts in Harry Maguire, Kyle Walker, John Stones, Kieran Trippier, Marc Guehi and Lewis Dunk are selected, as is Luke Shaw, despite the Manchester United man's severe lack of action in recent months due to injury.
Southgate has also called up a trio of Merseyside-based rearguard members, including Liverpool pairing Joe Gomez and Jarell Quansah - the latter of whom has not made his senior debut for his country yet - and Jarrad Branthwaite, who excelled for Everton in 2023-24.
Aston Villa's Ezri Konsa also makes the 33-man training squad after helping the Lions qualify for the Champions League, but there is no room for Chelsea trio Levi Colwill, Reece James and Ben Chilwell; the latter two are left to lament their frequent fitness problems.
AC Milan's Fikayo Tomori is also overlooked, while Arsenal right-back Ben White - who was revealed earlier this year to have made himself unavailable for selection - will not represent his nation at the Euros either.
Marcus Rashford, Jordan Henderson snubbed
Just six players have been included in the midfield troupe, including Liverpool vice-captain Trent Alexander-Arnold, his teammate Curtis Jones and Manchester United's Kobbie Mainoo, who put in two brilliant shifts in his first two England appearances in March.
After playing a fundamental role in Crystal Palace's phenomenal end to the campaign, Adam Wharton is also called up and benefits from the absence of Ajax's Jordan Henderson, whom Southgate had previously shown unwavering loyalty to amid heavy criticism of his Saudi Arabia transfer.
As expected, there is no room for Euro 2020 regular Kalvin Phillips, while Real Madrid's Jude Bellingham is listed as one of 12 attackers, joining Chelsea's Cole Palmer, Tottenham Hotspur's James Maddison and Crystal Palace's Eberechi Eze in that regard.
Manchester City's Jack Grealish is in despite his underwhelming season, but Marcus Rashford does not share the same fate and will not be going to Germany, having suffered a marked domestic decline in a Manchester United shirt this season.
Both Ollie Watkins and Ivan Toney will act as understudies to Harry Kane for at least another couple of weeks, meaning that Dominic Solanke is also omitted despite conjuring up 19 Premier League goals for Bournemouth in 2023-24.
England provisional squad in full:
Goalkeepers: Dean Henderson (Crystal Palace), Jordan Pickford (Everton), Aaron Ramsdale (Arsenal), James Trafford (Burnley)
Defenders: Jarrad Branthwaite (Everton), Lewis Dunk (Brighton), Joe Gomez (Liverpool), Marc Guehi (Crystal Palace), Ezri Konsa (Aston Villa), Harry Maguire (Manchester United), Jarell Quansah (Liverpool), Luke Shaw (Manchester United), John Stones (Manchester City), Kieran Trippier (Newcastle), Kyle Walker (Manchester City)
Midfielders: Trent Alexander-Arnold (Liverpool), Conor Gallagher (Chelsea), Curtis Jones (Liverpool), Kobbie Mainoo (Manchester United), Declan Rice (Arsenal), Adam Wharton (Crystal Palace)
Forwards: Jude Bellingham (Real Madrid), Jarrod Bowen (West Ham), Eberechi Eze (Crystal Palace), Phil Foden (Manchester City), Jack Grealish (Manchester City), Anthony Gordon (Newcastle), Harry Kane (Bayern Munich), James Maddison (Tottenham), Cole Palmer (Chelsea), Bukayo Saka (Arsenal), Ivan Toney (Brentford), Ollie Watkins (Aston Villa)