In 2019, Dahlkemper was the starting central defender for the national team beside Becky Sauerbrunn at the 2019 FIFA Women's World Cup in France, marking her first World Cup appearance. Dahlkemper and goalkeeper Alyssa Naeher were the only players to start every match of the tournament for the United States, with Dahlkemper playing every minute of the team's seven games aside from coming off in the 82nd minute against Chile in the group stage. Dahlkemper and the United States defeated the Netherlands 2–0 in the final to win the United States' fourth Women's World Cup title.