Southgate has picked a 25-man squad, which includes the likes of Norwich's Nathan Redmond and Tottenham's Harry Kane, for a tournament that four-time winners England have not participated in since 2005.
England's opener comes on May 22 against Qatar before they tackle fellow Group B opponents Brazil, South Korea and Colombia.
With England claiming six wins from seven matches so far during their European Championship qualification campaign, Southgate insists playing against non-European opponents will be a good test for his side.
"It is invaluable playing teams from different continents," Southgate said.
"We play mainly European teams at this age group. We think we need to expose our players throughout the age groups to more South American, North American, African and Asian teams.
"It is an important thing for their development and we want tough challenges. It is no use ducking the big opponents. We want to play the best teams and test ourselves against the best teams.
"Only then will we know exactly where we are so that was important for us this summer."
U21s regulars Tom Ince, Jesse Lindgard and Danny Ings are unavailable for the tournament as they are too old but have been included for Monday's European Championship qualifier against Wales.
Everton pair Ty Browning and Luke Garbutt and Brighton duo Solly March and Jake Forster-Caskey join Fulham striker Cauley Woodrow in Southgate's squad for the first time.
And Southgate hopes his new-look squad can continue playing the same brand of attacking football that has seen England score 24 goals in their first seven European Championship qualifiers.
"We've got three away games to finish the group with, which will be challenging," he said. "We've got a few new players coming in so you're not totally certain how that is going to pan out.
"We set off at the start to play a certain brand of football and to try and win while playing that brand of football. That will be our aim again on Monday night.
"We focus on performance and the way that we play and if you do that then results are a by-product of that."