Purpose: Understanding the experiences of people with developmental disabilities during the initial period of COVID-19 pandemic. Methods: Individuals with developmental disabilities and their caregivers completed baseline and up to five follow-up online surveys using the CRISIS-AFAR measures, between July 2020 and September 2021. We used qualitative (thematic analysis) and quantitative (MANOVA) analytic methods. Results: One hundred and eighteen participants (64 caregivers on individuals 6-62 years, 54 self-reporting individuals aged 17-55 years) completed baseline survey; 46 participants (23 caregivers, 23 self-reporting adults) completed [greater than or equal to] 1 follow-up. Qualitative themes included uncertainty, and negative and positive influences on behaviours and routines, daily life and mental wellness. Those experiencing positive impacts did not stably perceive so longitudinally. Conclusions: Despite both negative and positive influences on individuals with developmental disabilities and their families, the prolonged pandemic had wide-ranging repercussions. Emergency preparedness planning should consider the disruptive effects of public health measures on routine and support for this vulnerable population.