Background: This paper evaluates the user experience of a newly developed mindfulness and relaxation game designed to teach mindfulness skills to people with intellectual disabilities. Computer-assisted mindfulness programs have gained considerable attention among researchers in both adult and child populations. However, less is known about the experiences of people with intellectual disabilities who engage in computerised mindfulness programs. The present study aimed to explore the experiences of adults with intellectual disabilities and clinicians in using a computerised mindfulness and relaxation game. Method: Twelve adults (with a mild or moderate intellectual disability) and sixteen clinicians were individually interviewed. Thematic analysis was used to analyse and generate themes within the data. Findings: Three main themes with a number of subthemes were generated for people with intellectual disabilities including the following: (1) The Process of Mindful Island; (2) Fostering Relationships Through the Computer; and (3) The Impact of the Game. Three themes from clinician interviews were also generated including the following: (1) A Good Concept but More to Do; (2) Uncertainties Around Players' Understanding of Mindfulness; and (3) The Computer as a Tool to Build Relationships. The findings indicated that participants found the game an enjoyable experience and saw a number of benefits to engaging in it including perceived improved confidence and perceived reduction of worries. Conclusions: Mindfulness can be adapted to computer-assisted technology for use among people with intellectual disabilities and may foster a number of benefits.