The growing interest in citizen science has resulted in a new range of digital tools that facilitate the interaction and communications between citizens and scientists. Considering the ever increasing number of applications that currently exist, it is surprising how little we know about how volunteers interact with these technologies, what they expect from them, and why these technologies succeed or fail. Aiming to address this gap, JCOM organized this special issue on the role of User Experience (UX) of digital technologies in citizen science which is the first to focus on the qualities and impacts of interface and user design within citizen science. Seven papers are included that highlight three key aspects of user-focused research and methodological approaches. In the first category, "design standards", the authors explore the applicability of existing standards, build and evaluate a set of guidelines to improve interactions with citizen science applications. In the second, "design methods", methodological approaches for getting user feedback, analysing user behaviour and exploring different interface designs modes are explored. Finally, "user experience in the physical and digital world" explores crossovers with other fields to improve our understanding of user experiences and demonstrate how design choices not only influence digital interactions but also shape interactions with the wider world.