Recent developments in Information and Communication Technology (ICT) and ongoing digitalisation processes play key roles in the energy transition. It is often argued that digital technology has the potential to empower citizens and communities and thereby contribute not only to a more sustainable but also to a more democratic and fairer energy system. It is however unclear how the increasing number of frontrunner energy communities that enter the field of smart grids can benefit from these novel ICT solutions and meaningfully contribute to the sustainable energy transition. This paper explores how energy communities can mobilise ICT to enhance their agency in the energy transition. As part of a holistic multiple-case study approach, two energy communities were closely followed over a period of three years. Data were collected during project meetings and through semi-structured interviews. This paper observes that energy communities can mobilise ICT to change the way technology operates, strengthen collaboration to increase collective agency and, support their efforts in creating, disrupting, or maintaining institutions. The studied energy communities adopted a ‘fit and transform’ strategy in which they mobilised ICT to fit in the incumbent energy system in the short term, while aiming for transformation in the long term. ICT however also creates new challenges in the form of interoperability issues. This paper calls for more attention on the role of ICT when studying agency in unfolding sustainability transitions, especially in fields in which digital technology is believed to play a major role in the transformation.