Bilan was a part of the Croatian U-18 and U-20 teams as well as Croatian B national side. He made his debut for the senior Croatian national basketball team in August 2014 in a friendly against Canada. He was the last player to be removed from the preliminary squad for the 2014 World Cup. He represented Croatia at the EuroBasket 2015, where they were eliminated in the eighth finals by Czech Republic. At this tournament he was the third choice for the center position and did not spend much time on court. A year later, after Ante Tomić and Justin Hamilton canceled playing in the tournament, he became the first-choice center in Croatia's successful appearance at the 2016 FIBA World Olympic Qualifying Tournament. He played at the 2016 Summer Olympics where Croatia came 5th. He rejected the call-up for the 2017 EuroBasket, but played again for the Croatia national basketball team at the 2019 FIBA Basketball World Cup qualification games.