Adolescence is a time of psycho-social and physiological changes, with increased associated health risks including vulnerability to pregnancy, HIV, sexually transmitted infections, and gender-based violence. Adolescent learners, from three townships in South Africa, participated in a 44 session, after-school asset-building intervention (GAP Year), over 2 years providing sexual and reproductive health (SRH) education. This paper explores adolescent learners' SRH, sexual risk and rights knowledge; perceptions about transactional sex; and contraceptive method preferences and decision-making practices. The intervention was conducted in 13 secondary schools across Khayelitsha, Thembisa, and Soweto, South Africa. A baseline survey collected socio-demographic data prior to the intervention. Overall, 26 focus group discussions (FGDs): 13 male and 13 female learner groups, purposively selected from schools, after completing the intervention (2 years after baseline data collection). Descriptive analyses were conducted on baseline data. Qualitative data were thematically coded, and NVivo was used for data analysis. In total, 194 learners participated in the FGDs. Mean age at baseline was 13.7 years (standard deviation 0.91). Participants acquired SRH and rights knowledge during the GAP Year intervention. Although transactional sex was viewed as risky, some relationships were deemed beneficial and necessary for material gain. Negative healthcare provider attitudes were the main barrier to healthcare service utilisation. There was awareness about the benefits of contraceptives, but some myths about method use. The injectable was the preferred contraceptive method, followed by the implant, with equal preference for condoms and oral pill. An afterschool intervention at school is a viable model for the provision of SRH and rights education to learners. Recommendations include the need for risk reduction strategies in the curriculum, dealing with misconceptions, and the promotion of informed decision making. Endeavours to ensure health services are youth friendly is a priority to limit barriers to accessing these services.