went on to make 11 appearances for the U19 side. In August 2015, Klostermann was called up for the Germany U21 for the first time. He made his Germany U21 debut, coming on as a late substitute, in a 2–1 win over Denmark U21 on 3 September 2015. Almost a year absent, Klostermann was called up for the Germany U21 squad again and played 45 minutes, in a 2–1 loss against Hungary on 1 September 2017 Two months later, he scored two goals in two matches against Azerbaijan U21 and Israel U21. On 27 March 2018, Klostermann captained the U21 side for the first time, starting the whole game, in 0–0 draw against Kosovo U21. He went on to captain the side on three more occasions by the end of 2018. In June 2019, he was called up by Germany U21 for the UEFA European Under-21 Championship in Italy. Klostermann started all four matches and helped Germany U21 side reach the final. But in the final, he started the whole game, as Germany U21 lost 2–1 against Spain U21. Despite this, Klostermann were among six Germany U21 players to be named UEFA European Under-21 Championship Team of the Tournament. 2016 Summer Olympics In July 2016, Klostermann was called up to be a part of the squad for the 2016 Summer Olympics. Klostermann played his first match of the tournament on 4 August 2016, starting the whole game, in a 2–2 draw against Mexico U23. He then set up one of the goals, one of which was for Nils Petersen, who scored five goals, in a 10–0 win over Fiji U23 on 10 August 2016. He then scored his first goal of the tournament on 17 August 2016, in a 2–0 win over Nigeria U23 in the semi–finals, which sends them through to the final. Although Germany U23 lost in the final against Brazil U23, He went on to make six appearances for the side, playing in the left–back position, where Germany won the silver medal. After the tournament, Klostermann revealed that he auctioned his silver medal, alongside Alexandra Popp. Later in November, the team were honoured with Silbernes Lorbeerblatt. Senior team Klostermann received his first call up to the senior national team in March 2019 for the friendly match against Serbia and UEFA Euro 2020 qualifying match against the Netherlands. He made his Germany debut, playing the whole game, in