The objective of this study was to understand the experiences of people living with dementia and their informal carers’ taking part together (in dyads) in Tai Chi classes and the aspects influencing their adherence. Dyads’ experiences of taking part in Tai Chi classes for 20 weeks within the TACIT Trial were explored through class observations (n = 22 dyads), home-interviews (n = 15 dyads), and feedback. Data were inductively coded following thematic analysis. Tai Chi classes designed for people with dementia and their informal carers were enjoyable and its movements, easy to learn. Facilitators of participants' adherence were the socializing component and their enjoyment of the classes, whereas unexpected health problems were the main barrier. Finding the optimal level of challenge in the class setting might be crucial for people with dementia to feel satisfied with their progression over sessions and enable their continued participation.