This study aims to examine the effectiveness of mHealth delivered through LINE application in improving physical activity of older adults. This was a parallel, two-arm, randomized controlled trial, single-blind allocation to experimental and control groups. The sample consisted of 91 individuals (46 experimental and 45 control groups) aged 45���years or older, and had internet access. Intervention group received customized activities focused on raising awareness and knowledge provision for 8���weeks. Out of 91 participants, 82 completed the study (41 in each group). Comparison of Mean Difference values within groups found a significant difference at ���<���.05 (t���=���2.294). The experimental group increased their PA by 7.2���min on average, while the control group decreased to 44.1���min. Subgroup that fully complied with the activity process had a significantly higher percentage of adequate PA at P���=���.01 level (���=���7.853**). Tailoring activity content to older adults' diverse lifestyles via a Mobile Health application can effectively boost PA levels by meeting their needs conveniently and quickly.Clinical trial registration: Thai Clinical Trials Registry (TCTR) TCTR20240422004.
