The head coach took an U20s squad to the annual competition in France, where the Three Lions finished in fourth place after five games in 11 days.
And with the majority of that group able to feature in next summer’s Euro Under-21 Finals and also still young enough for the one after that in 2017, Southgate has been encouraged by what he has seen.
There were nine players included in the squad for Toulon who had never featured for the Under-21s before and everyone in the group was given the chance to start at least two games in the competition.
"There’s been a big plus in terms of individuals who we haven’t had with us before and how they’ve coped and come through," revealed Southgate, whose side were beaten 1-0 by Portugal in Sunday’s third-fourth place play-off game.
"We’ve got five or six lads this summer who make us a stronger group and a lot of the ‘94s [birth dates] can play in the next Euros as well.
"There’s a depth of players there and when I pick the squad for our next games in September and October, it will be a lot harder.
"These lads have been desperate to come and desperate to be a part of it, so it’s going to be tough to select.”
Added to those players will be a number of this season’s U19s squad, who were desperately unlucky to miss out on qualifying for their own Euro Finals last month.
Video highlights from the third-fourth place play-off game between England and Portugal
Southgate refrained from picked any of those from Noel Blake’s group for the trip to Toulon, but admits several of them could be challenging in the near future too should they continue to progress.
"There is a real depth of talent in a few of the age groups below too," he added.
"You see the U17s who have just win their Euro title and it’s a similar situation with the U19s as well.
"We could have brought Calum Chambers [to Toulon], who would have benefited from the experience, but the U19s had their qualifiers that week and we wanted them to have the best opportunity to qualify.
"But all of that age group are eligible for us next year so the likes of Calum, Jordon Ibe, Josh Murphy, Sam Gallagher and James Wilson and there will be competition for the lads who are here and those who are not here."