A recent meta-analysis provided proof of efficacy for mobile technology to increase physical activity or weight loss in the short term. Videoconferencing may also be effective, especially as it reduces the barriers related to face-to-face physical activity interventions. Both technologies seem particularly interesting for bariatric surgery management, but their long-term effects on physical activity maintenance are unknown. Moreover, the mechanisms underlying their effectiveness, such as technology acceptability and motivational processes, have not been examined.The objectives of this study are to determine the effects of two technology-based (mobile technology and videoconferencing) physical activity programmes after bariatric surgery compared with standard care and to assess the contribution of acceptability and motivational mechanisms in explaining these effects on physical activity, physiological measures and health indicators.