Eligible to represent Germany or Kazakhstan, Bauer revealed that he had rejected an offer from the latter in February 2015 in hopes of representing Germany. The next month, he received his first call-up to the Germany U20 side and represented them at the FIFA U-20 World Cup in New Zealand that summer.
He was part of the squad for the 2016 Summer Olympics, where Germany won the silver medal.
On 14 September 2023, Robert Bauer has announced on his Instagram that he converted to Islam.
He further mentioned that he came to Islam through his wife and her family. And thanked all for the journey on social media.