- World Indoor Championships: Birmingham 2018 - Silver (Pentathlon)
- European Championships: Amsterdam 2016 - Bronze (Heptathlon)
- European Indoor Championships: Belgrade 2017 - Silver (Pentathlon)
- European U23 Championships: Tallinn 2015 - Bronze (Heptathlon)
Ivona Dadić was born on 29 December 1993 in Wels, Austria to Nine and Danica Dadić, who are from Bugojno, Bosnia and Herzegovina. Dadić was raised as a Roman Catholic. At the age of nine she won her first competition. Her brother Ivan died in 2008 in car accident so she has a tattooed cross on her left hand with his name. In 2015 Dadić won a bronze medal at the 2015 European U23 Championships with 6033 points. One year later she won a bronze medal at the 2016 Amsterdam with 6408 points.
Dadić competed at the 2012 Olympic Games in London. She achieved three personal bests—in long jump, javelin, and the 800 meter—finishing 25th overall.