Whilst dancing with Kiev Ballet, Cojocaru re-applied to the Royal Ballet in London, but was only invited to audition for the corps de ballet. She attended an audition for the company whilst on leave from Kiev Ballet and was offered a contract. Doubtful of development opportunities elsewhere, she accepted the contract and joined the company in November 1999. She was subsequently promoted to principal dancer in 2001. In 2004, she received the Prix Benois de la Danse for her portrayal of "Cinderella".