INTRODUCTION: Sexual health is essential for general health and well-being. Sexual health services for middle-aged and older adults are not prioritised and optimising available services for this population is often overlooked. Not much is known about preferences for accessing sexual health services among middle-aged and older people or level of satisfaction with current services. The aim of this study is to explore preferences for seeking sexual health services among middle-aged and older adults in the UK. This study will use discrete choice experiments (DCEs) including initial qualitative interviews followed by the survey, which have been used as a tool to explore preferences in various health service delivery. METHODS AND ANALYSIS: The project will be carried out in two phases. First, we will conduct in-depth semi-structured interviews with 20-30 adults (aged 45+), including disabled people, and those from sexual minority groups resident in the UK. Interviews will explore indications, preferences and factors related to accessing sexual health services. Themes and subthemes emerging from the analysis of the interviews will then be used to design the choice sets and attribute level for the DCEs. For the second phase, for the DCEs, we will design choice sets composed of sexual health service delivery scenarios. The software Ngene will be used to develop the experimental design matrix for the DCE. We will use descriptive statistics to summarise the key sociodemographic characteristics of the study population. Multinomial logit, latent class and mixed logit models will be explored to assess sexual health service preferences and preference heterogeneity. ETHICS AND DISSEMINATION: Ethical approval for both parts of this study was granted by the Research and Ethics Committee at the London School of Hygiene & Tropical Medicine. Findings from this study will be disseminated widely to relevant stakeholders via scheduled meetings, webinars, presentations and journal publications.