Background <p>Out-of-home mobility is crucial for maintaining autonomy and participation in older adults and plays a key role in preventing cognitive decline, social isolation, and frailty. However, there is a notable scarcity of interventional research aimed at promoting out-of-home mobility, particularly in rural areas where environmental barriers to mobility are pronounced and older adults are at risk of limited mobility. This study aimed to evaluate the effectiveness of a physiotherapist-led motivational counselling intervention designed to enhance out-of-home mobility in older adults living in rural communities.</p> Methods <p>A randomized controlled trial was conducted among community-dwelling older adults aged 75 and above, residing in a rural region of Germany. Participants in the intervention group received motivational counselling focusing on goal setting, social network activation, and the use of regional resources, while the control group received an informational leaflet. The primary outcome, out-of-home mobility (time out of home), was assessed using GPS tracking over seven consecutive days at T₀ (baseline), and at T₁ and T₂ (4 and 12-week follow-ups). Secondary outcomes included GPS-derived convex hull, self-reported life-space mobility, physical activity, depressive symptoms, health status, as well as frailty. Mixed-effects models were employed and effect sizes were estimated using Cohen’s d.</p> Results <p>A total of 212 participants (mean age 81.54 ± 4.0 years) were included, with 108 participants in the intervention group. Both groups showed an increase in out-of-home mobility over time. However, no significant intervention effects were observed at T₁ and T₂ for either the primary or secondary outcomes (all <i>p</i> &gt; .05). Subgroup analyses revealed significant interaction effects for women, pre-frail/frail individuals, participants aged 81 and older, and those residing in the most rural municipalities (≤ 15,000 inhabitants) for physical activity, health status and life-space mobility.</p> Conclusions <p>Both, the intervention and control groups exhibited an increase in out-of-home mobility. However, no differential intervention effect was observed, possibly reflecting the already active baseline characteristics of the sample. Subgroup analyses identified significant interaction effects among particular subgroups, pointing towards a greater necessity for targeted interventions in future investigations. Further research is warranted to explore how to effectively improve mobility in older rural populations.</p> Trial registration <p>The trial was prospectively registered at the DRKS registry on 5 May 2021 (Deutsches Register Klinischer Studien) with the study identity number DRKS00025230. Ethical approval was given by the Ethics Committee of Charité – Universitätsmedizin Berlin (EA1/052/20).</p>