Pope and Tarkowski are joined in the senior setup for the first time by Swansea City centre-back Alfie Mawson and Bournemouth midfielder Lewis Cook as Southgate names a 27-man squad for the friendlies with the Netherlands and Italy.
Manchester United's Ashley Young is also included, but there is no spot for Fulham attacker Ryan Sessegnon, while Bournemouth's Callum Wilson is left out despite speculation that the forward would receive a position.
England, who are without Harry Kane through injury, will travel to the Netherlands on March 23 before hosting Italy on March 27.
Goalkeepers: Joe Hart, Jordan Pickford, Jack Butland, Nick Pope
Defenders: Kyle Walker, Kieran Tripper, Ryan Bertrand, Danny Rose, John Stones, James Tarkowski, Alfie Mawson, Joe Gomez, Harry Maguire
Midfielders: Eric Dier, Jack Wilshere, Jordan Henderson, Jake Livermore, Adam Lallana, Alex Oxlade-Chamberlain, Dele Alli, Raheem Sterling, Ashley Young, Jesse Lingard, Lewis Cook
Forwards: Danny Welbeck, Jamie Vardy, Marcus Rashford