Karuna Jain began her international cricket career with a 64 against West Indies on ODI debut. She was part of the team that made it to the final of the 2005 Women’s World Cup final, where India eventually lost to Australia. Jain’s contribution was crucial in India’s 4-1 series win against England in 2005 where she scored a century in the final. At a young age of 20, Jain also captained the Indian side to Pakistan in the same year.
Poor form kept her out of India’s successful defence of the Asia Cup in 2006. On her return, two months later, Jain scored three half-centuries from seven matches in the Quadrangular tournament of 2007.