Abstract Background We have co-designed a tailored blended physiotherapy intervention for people with progressive multiple sclerosis (PwPMS) who often struggle to access support for physical activity. Underpinned by self-management principles, the Lifestyle, Exercise and Activity Package for people with Multiple Sclerosis (LEAP-MS) intervention incorporates face-to-face or online physiotherapy coaching sessions with an accompanying online physical activity platform. The LEAP-MS platform is a multi-user system enabling user and physiotherapist to co-create activity plans. The LEAP-MS platform consists of an information and activity suite, interactive components enabling selection of exercises into an activity programme, goal setting and activity logging. The platform also facilitates online remote support from a physiotherapist through an embedded online messaging function. We aim to evaluate the LEAP-MS platform in a feasibility trial. Methods LEAP-MS will be evaluated within a single-arm feasibility study with embedded process evaluation. After registration and initial eligible screening, 21 participants will be required to complete baseline self-completion measures. This will be followed by an initial home-based or online coaching session with a physiotherapist (who has received tailored self-management and digital resource training) and access to the online intervention for an initial 3-month period. During this period, participants are given the option to request up to five further home-based or online physiotherapy coaching sessions. Follow-up questionnaires and semi-structured interviews will be administered 3 months after baseline with participants and intervention physiotherapists. The LEAP-MS platform will be available to participants for a further 3 months. Usage of the LEAP-MS platform will be tracked during the full 6-month period and final follow-up will be conducted 6 months after baseline. Discussion Feasibility outcomes (recruitment, retention, intervention uptake and safety) will be reported. The process evaluation will be undertaken to identify possible mechanisms for any observed effects. The data will inform full-scale evaluations of this co-produced, blended physiotherapy intervention. Trial registration ClinicalTrials.gov, NCT03951181. Registered 15 May 2019