Most of internal female migrants are young, at risk of unintended pregnancy, unsafe abortion. This paper aims to describe premarital sexual behaviors and contraceptive use among unmarried female migrant workers in industrial parks, Vietnam. A cross-sectional survey was completed with a sample of 2,996 workers aged 18-49 years. We found that premarital sex rate was 12.6%. Most of them were inconsistent contraceptive users. About 27.8% did not use any contraception in the last 6/months. Condom was the most popular contraceptive used (61.3%) and obtained through pharmacies, kiosk systems. Contraceptive use was significantly associated with age, education, private companies, and income.