Identifying women aged 30-39 years at increased risk of developing breast cancer could allow them to consider screening and preventive strategies. Research is underway to determine the feasibility of offering breast cancer risk assessment to this age group. However, it is unclear how best to deliver and communicate risk estimates to these women, in order to avoid potential harms such as undue anxiety and increase benefits such as informed decision-making. This study aimed to investigate women's views on, and requirements for, this proposed novel approach to risk assessment. A cross-sectional qualitative design was used. Thirty-seven women aged 30-39 years with no family history or personal history of breast cancer participated in seven focus groups (n = 29) and eight individual interviews. Data were analysed thematically using a framework approach. Four themes were developed. Acceptability of risk assessment service concerns the positive views women have towards the prospect of participating in breast cancer risk assessment. Promoting engagement with the service describes the difficulties women in this age group experience in relation to healthcare access, including mental load and a lack of cultural awareness, and the implications of this for service design and delivery. Impact of receiving risk results focuses on the anticipated impacts of receiving different risk outcomes, namely, complacency towards breast awareness behaviours following low-risk results, an absence of reassurance following average-risk results and anxiety for high-risk results. Women's information requirements highlights women's desire to be fully informed at invite including understanding why the service is needed. In addition, women wanted risk feedback to focus on plans for management. The idea of breast cancer risk assessment was received favourably among this age group, providing that a risk management plan and support from healthcare professionals is available. Determinants of acceptability of a new service included minimising effort required to engage with service, co-development of invitation and risk feedback materials and the importance of educational campaigning about the potential benefits of participation in risk assessment.