A best of 2:36:14 hours came at the 2015 Seoul International Marathon, though she was eleventh overall in the higher calibre field. She closed the year with wins at the Incheon Half Marathon (setting a new best of 74:15 minutes) and won the National Games Marathon title. March 2016 saw Ahn set new bests in the half marathon (73:41 minutes) and the marathon (2:32:15). These performances earned her selection for South Korea at the 2016 Summer Olympics. She finished 42nd at the 2016 Olympic marathon, ahead of teammate Lim Kyung-hee, but some way behind her Northern rivals Kim Hye-song and Kim Hye-gyong.