Koina Mitra started her modeling career while she was still in school. In 2001, she won the beauty pageant Gladrags Mega Model India 2001. She later became one of the top-12 semifinalists of Miss Intercontinental Pageant in Germany out of 84 countries. Over the years, Mitra has done commercials for Mirinda, Clinic All Clear, Maruti Alto, Jewellery and beauty products. She has done many fashion weeks in Milan and Beijing.