ObjectivesTo investigate the efficacy of health coaching and a web‐based program on survivor physical activity (PA), weight, and distress management among stomach, colon, lung and breast cancer patients.MethodsThis randomised, controlled, 1‐year trial conducted in five hospitals recruited cancer survivors within 2 months of completing primary cancer treatment who had not met ≥1 of these behavioural goals: (i) conducting moderate PA for at least 150 minutes/week or strenuous exercise for over 75 minutes per week or, in the case of lung cancer patients, low or moderate intensity exercise for over 12.5 MET per week, (ii) maintaining normal weight, and (iii) attaining a score >72 in the Post Traumatic Growth Inventory (PTGI). Participants were randomly assigned to one of three groups: the control group, a web‐only group, or a health coaching + web group. The primary endpoint was based on a composite of PA, weight, and PTGI score at 12 months.ResultsPatients in the health coaching + web group (difference = 6.6%, P = .010) and the web‐only group (difference = 5.9%, P = .031) had greater overall improvements across the three‐outcome composite than the control group. The health coaching + web group had greater overall improvement in PTGI (difference = 12.6%; P < .001) than the control group, but not in PA and weight.ConclusionThe web‐based program, with or without health coaching, may improve health behaviours including PA, weight, and distress management among cancer survivors within 2 months of completing primary cancer treatment. The web‐based program with health coaching was mainly effective for reducing psychological distress.