She won the gold medal at the 2014 European Junior Women's Championships in Katowice, Poland.[6][7] She participated at the 2014 World Championships in Tashkent, Uzbekistan without success.
Tosun captured the bronze medal at the European Under-23 Championships in Wałbrzych, Poland.[2] She competed in the 63 kg event of the 2015 European Games in Baku, Azerbaijan.
In 2023, she won the silver medal in the 72 kg event at the European Wrestling Championships held in Zagreb, Croatia.[29] She was beaten by Romanian Alexandra Nicoleta Anghel 4-4 and won the silver medal. In the quarterfinals, she won the semifinals with a 6–0 win fall over Russian-born Israeli Ilena Kratysh. After defeating Italian Dalma Caneva with a 10-0 technical superiority in this round, Tosun reached the final.[30]
Tosun won the gold medal in the women's 68kg event at the 2023 World Wrestling Championships held in Belgrade, Serbia.[31] Buse Tosun Çavuşoğlu reached the semifinals by defeating Moldovan Irina Rîngaci in the second round with a 4-2 pinfall, Mexican Alejandra Rivera in the third round with a 6-0 pinfall, and Czech Adéla Hanzlíčková 8-0 in the quarterfinals. In the semifinals, she defeated her Japanese opponent Ami Ishii by 11-1 technical superiority to reach the final.[32] Tosun also earned a quota place for Turkey for the 2024 Summer Olympics in Paris, France.[33]
2024–present
Tosun won the gold medal at the 2024 European Wrestling Championships in Bucharest, Romania, in the women's freestyle 68 kg, defeating Ukraine's Tetiana Rizhko 5-2 in the final.[34] She had reached the final by pinning Azerbaijan's Khanum Velieva, an individual independent competing for Russia, 4-1 in the quarterfinals and defeating Czech Adéla Hanzlíčková 10-9 in the semifinals.[34][35]
At the 2024 Paris Olympics, she lost in the first round to Amit Elor of the United States, 10-2.[36][37] She went on to win one of the bronze medals in the event.[37]