Background: Few individuals with metastatic prostate cancer have access to prostate cancer-specific exercise support, despite demonstrated benefits. eHealth tools, such as websites, may be viable options for increasing access. To be effective and acceptable, future eHealth websites need to consider end-users' perspectives, capacity and needs. We aim to provide insight into these factors by exploring daily priorities, activities and health literacy of individuals with metastatic prostate cancer and their perspectives towards exercise and exercise-based web-based eHealth interventions. Methods: Semi-structured interviews explored participant's experiences and understanding of their disease, exercise levels, advice received from health care providers, as well as acceptability of and suggested content for an eHealth tool. A thematic analysis was undertaken. Results: Interviews were conducted with eighteen Australians (55-83 years; M = 71.5, SD = 8.9) living with metastatic prostate cancer. Needing to perform daily responsibilities was a key priority. Participants had limited understanding of the benefits of prostate cancer-specific exercise, and less than half discussed exercise with their health team. Fourteen men felt they could report metastases location, but only four could provide detailed information, which has clinical implications for exercise prescription. A potential web-based intervention was considered acceptable by seventeen men for reasons such as affordability, accessibility and convenience. User-friendly design and practitioner support were important. Conclusions: Results identified key aspects useful for person-centred design of exercise programs. Participants were positive towards the proposed web-based tool and expressed the need for individualised, user-friendly and reliable information with support from a professional embedded. Lastly, not all participants could accurately report metastasis locations.