England reached the semi-finals of the 2018 competition in Russia before losing to Croatia, and will now switch their attention to the upcoming internationals with Spain and Switzerland.
The Three Lions will open their UEFA Nations League campaign against Spain on September 8, before taking on Switzerland in a friendly on September 11.
"Really we're on the back of a successful tournament. We picked a squad in the summer that we believed were the best players for that," Southgate told reporters.
"Not too much will have changed in that time because we reached the semi-final and there's only been three league games. We wanted some continuity."