On 30 May 2016, Neustädter was granted Russian citizenship, having received his new Russian passport at the Russian Consulate in Bonn.
In July 2016, after turning down a new contract at Schalke, Neustädter signed a three-year deal at Fenerbahçe S.K. of Turkey.
In January 2016, Neustädter met with members of the Russian Football Union in order to be able to possibly play for the Russia national team in the future. On 21 May 2016, he was called up to represent Russia at UEFA Euro 2016. On 1 June 2016, Neustädter made his debut for Russia, in a 2–1 friendly loss to the Czech Republic, as a 64th-minute substitute. He started Russia's first two games during the final tournament in France, where Russia failed to proceed through the group stage.