This study aimed to qualitatively investigate young women's preferences for preconception intervention strategies to promote physical and mental health in a rapidly transitioning, urban setting. Four semi-structured focus group discussions were conducted with young women (n = 29, 18–24 years old) from Soweto, South Africa. Qualitative data were thematically analysed. Two main themes were identified: 1) challenges and needs of intervention beneficiaries; and 2) preferences for intervention strategies (content and delivery). The challenges participants mentioned could be classified as those relating to social pressure, identity, and socioeconomic circumstances. Mental health support appeared to be a greater need than physical health, and this featured in their preferences for intervention content, although a number of physical health topics were also mentioned (healthy eating and contraception). Participants had mixed preferences for intervention materials, ranging from printed to electronic and mobile resources. Their preferences for intervention activities ranged from educational sessions, to fun and interactive practical activities, and activities they could take home. Community health workers (CHWs) were the preferred agent of delivery for interventions, though participants emphasised the importance of CHWs having appropriate interpersonal skills and own life experience. Some women preferred one-on-one sessions with a CHW, while others preferred group sessions. While recognising the value of family sessions, young women were less enthusiastic about this approach. These findings provide valuable formative data for developing effective interventions to optimise young women's preconception health in urban Africa. These contextual realities should be acknowledged when addressing key physical and mental health issues facing young women.