BACKGROUND: Trial participation can allow people with CF early access to CFTR modulator therapies, with high potential for clinical benefit. Therefore, the number of people wishing to participate can substantially exceed the number of slots available. We aimed to understand how the CF community thinks slots to competitive trials should be allocated across the UK and whether this should be driven by clinical need, patients' engagement/adherence or be random. For the latter, we explored site-level versus registry-based, national randomisation processes. METHODS: We developed an online survey, recruiting UK-based stakeholders through social media, newsletters and personal contacts. Closed questions were analysed for frequencies and percentages of responses. Free-text questions were analysed using thematic analysis. RESULTS: We received 203 eligible responses. Overall, 75% of stakeholders favoured allocation of slots to individual sites based on patient population size, although pharma favoured allocation based on previous metrics. Currently, few centres have defined strategies for allocating slots locally. At face-value, stakeholders believe all eligible participants should have an equal chance of getting a slot. However, further questioning reveals preference for prioritisation strategies, primarily perceived treatment adherence, although healthcare professionals were less likely to favour this strategy than other stakeholder groups. The majority of stakeholders would prefer to allocate slots and participate in trials locally but 80% said if necessary, they would engage in a system of national allocation. CONCLUSIONS: Fair allocation to highly competitive trials does not appear to have a universally acceptable solution. Therefore, transparency and empathy remain critical to negotiate this uncertain territory.