INTRODUCTION: Antimicrobial-resistant gonorrhoea poses a significant global public health threat. In response, the UK launched the world's first gonorrhoea vaccination programme using a 4CMenB vaccine, targeting individuals at high risk of bacterial sexually transmitted infections (STIs). Understanding attitudes and acceptability among sexual health service users is essential to inform successful implementation. METHODS: The NAVIGATE study employed a mixed-methods design, combining an online survey (n=395) with semi-structured interviews (n=15) among UK adults who had previously accessed sexual health services. The survey included demographic questions, the validated Vaccination Attitudes Examination scale and items assessing the acceptability of gonorrhoea vaccine. Interviews explored deeper perceptions of vaccination, trust and delivery preferences. Quantitative data were analysed descriptively and qualitative data thematically using Braun and Clarke's framework. RESULTS: Participants showed high general vaccine confidence, with 92.2% strongly supporting a gonorrhoea vaccine programme. Acceptance was driven by concerns about antimicrobial resistance and trust in UK regulatory systems. Stigma and structural barriers, such as fear of judgement, cost and inconvenient delivery settings, were key factors influencing access. Participants favoured delivery through sexual health clinics and LGBTQ+ venues and strongly endorsed peer-led outreach. Partial efficacy of the proposed vaccine was accepted when transparently communicated. Concerns over personal costs emerged as potentially worsening inequalities. CONCLUSIONS: While overall acceptability was high, successful uptake requires delivery that is trusted, stigma-free, accessible and clearly communicated. Policy recommendations include ensuring free access, leveraging peer-led campaigns and delivering vaccination in low-barrier settings. Monitoring by demographic group is essential to prevent inequities. These insights are crucial as the UK's pioneering programme generates global evidence for future STI vaccine policy.