The Three Lions kick off their campaign with a rematch of the World Cup semi-final of three years ago, which they lost to the eventual runners-up.
Victory is always key in the three-match group stage and Southgate has selection decisions to make as England aim to start on the front foot.
Southgate has opted for a back four of late given Harry Maguire’s fitness issues – the Manchester United centre-back misses out this afternoon.
Further forward, question marks over Jordan Henderson’s fitness means he is on the bench and Kalvin Phillips gets the nod alongside Declan Rice, with Mason Mount further forward in a three behind Harry Kane.
With captain Kane’s spot guaranteed, it leaves Raheem Sterling and Phil Foden in support. Jadon Sancho does not make the squad.
Confirmed starting lineups
England XI: Pickford; Walker, Mings, Stones, Trippier; Phillips, Rice; Foden, Mount, Sterling; Kane
Croatia XI: Livakovic; Vrsaljko, Caleta-Car, Vida, Gvardiol; Brozovic; Kramaric, Modric, Kovacic, Perisic; Rebic
Goalkeepers: Dean Henderson, Sam Johnstone, Jordan Pickford
Defenders: Ben Chilwell, Conor Coady, Reece James, Harry Maguire, Tyrone Mings, Luke Shaw, John Stones, Kieran Trippier, Kyle Walker, Ben White
Midfielders: Jude Bellingham, Jordan Henderson, Mason Mount, Kalvin Phillips, Declan Rice
Forwards: Dominic Calvert-Lewin, Phil Foden, Jack Grealish, Harry Kane, Marcus Rashford, Bukayo Saka, Jadon Sancho, Raheem Sterling
Goalkeepers: Lovre Kalinic, Dominik Livakovic, Simon Sluga
Defenders: Domagoj Vida, Dejan Lovren, Sime Vrsaljko, Borna Barisic, Duje Caleta-Car, Josip Juranovic, Domagoj Bradaric, Mile Skoric, Josko Gvardiol
Midfielders: Luka Modric, Mateo Kovacic, Marcelo Brozovic, Milan Badelj, Mario Pasalic, Nikola Vlasic, Luka Ivanusec
Forwards: Ivan Perisic, Andrej Kramaric, Ante Rebic, Josip Brekalo, Bruno Petkovic, Mislav Orsic, Ante Budimir