Objectives The unmet needs of contraception can lead to unintended pregnancy and transmission of sexually transmitted infections (STI). Therefore, this study aimed to evaluate the contraception use, knowledge, and attitude on STI among students under Royan University of Bhutan (RUB). Methods This was a cross-sectional study using an online questionnaire. The questionnaire was developed in Google forms and the link was shared through the college WeChat groups. The questionnaire consisted of four parts on socio-demographic, sexual behaviour and contraceptive use, knowledge, and attitude on STIs. All the students under RUB were invited to participate voluntarily in this study. The socio-demography was presented in frequency and proportion. Result A total of 1,283 students participated in this survey and 55.0% (701) were females. Of this, 29.4% (377) were sexually active and 94.4% reported using modern contraception. Commonly used contraceptives were: condoms (83.8%, 316) and emergency contraceptives (20.6%, 78), respectively. The mean knowledge and attitude scores on STI were 9.94 (range 2-20) and 12 (range 2-14), respectively. Good knowledge and attitude on STI were reported in 53.2% (683) and 70.1% (899) of participants. Conclusion Students reported average knowledge and a good attitude towards STI. Contraceptive use among university students was low. There is a need to strengthen health education on STIs in schools and universities. All forms of contraceptives especially condoms should be made easily available to sexually active people.