Sexual health is integral to overall well-being, yet the needs and desires of middle-aged and older adults are often overlooked. This study aimed to understand the sexual health service preferences of adults aged 45 and older to enhance service accessibility in the UK. We conducted a Discrete Choice Experiment (DCE) in three stages: concept elicitation, refinement, and implementation. Attributes and levels were determined through 22 semi-structured interviews, followed by pilot testing. The DCE survey was implemented using Qualtrics XM with conjoint project features. We employed a random parameters logit model to estimate attribute importance and level preferences, and a latent class model to identify groups with similar preferences. The analysis included 200 responses (62.5% female, 35.5% disabled, 26.0% sexual minority; median age was 53). Service utilisation preferences were primarily influenced by delivery mode (Relative Importance (RI): 32%), location (RI: 18%), and cost (RI: 16%). Participants preferred face-to-face interactions at sexual health clinics and showed a willingness to pay for private services. Extra support and consultation style had minor impacts. No preference differences were found among disabled people, while sexual minorities preferred conventional messaging. Middle-aged and older adults prioritise face-to-face consultations at sexual health clinics over cost considerations. Aligning service delivery with these preferences could significantly improve the accessibility and uptake of sexual health services for adults aged 45 and older in the UK.