Ko Sung-hyun
Widjaja started the 2015 season by competing at the Malaysia Masters Grand Prix Gold with Edi Subaktiar. They reached in to the semifinals round, but lost to their teammates Praveen Jordan and Debby Susanto. The duo then took the title at the Austrian Open. Widjaja and Subaktiar made their first appearance at the semifinals of the BWF Super Series event in India Open, and at the China Masters Grand Prix Gold, they grabbed the runner-up podium. In August 2015, she qualified to compete at the World Championships in Jakarta as the 12th seeded with Subaktiar. They finished in the third round, after defeated by the 8th seeded from South Korea Ko Sung-hyun and Kim Ha-na.