ObjectivesRural Australian adults are consistently identified as insufficiently active, likely due to challenges implementing community-based physical activity programs in rural settings. On-line strategies to promote physical activity may be particularly effective in rural settings where isolation and scarcity of qualified support are potential barriers. The Rural Environments and Community Health (REACH) study evaluated the effectiveness of an online-delivered walking intervention among South Australian rural adults. DesignRandomised controlled study design. MethodsA twelve-week intervention, with six- and twelve-month follow-up, was conducted. Participants (n=171; 50.6±12.5years), recruited through flyers, local newspapers and radio, were randomised to comparison or intervention groups and received a pedometer. The intervention group received access to the REACH website and personalised step goals based on ratings of perceived exertion and daily affect. The comparison group received a paper diary and generic step goals. Outcome measures were accelerometry-assessed sedentary, light (LPA) and moderate-to-vigorous (MVPA) physical activity. Linear mixed models assessed changes over the intervention and follow-ups. ResultsSedentary time decreased, and LPA and MVPA increased in both groups across the intervention (p<0.05). The intervention group demonstrated a larger increase in LPA at six-month follow-up relative to comparison (p<0.05). Both groups decreased sedentary time, overall and in bouts ≥30min, between baseline and twelve-month follow-up (p<0.05). From baseline to twelve-month follow-up, MVPA (total min and bouts ≥10min) declined more in the comparison group than the intervention group (p<0.05). ConclusionWhile increased physical activity and decreased sedentary time were observed in both groups during the intervention period, maintenance was only observed for LPA at six-month follow-up in the intervention group. By twelve-month follow-up, post-intervention improvements had largely disappeared, suggesting that additional research is needed to identify ways to improve long-term adherence.