Unraveling the impact of COVID-19 on the spatio-temporal mobility patterns of microtransit is part of MPC project 608, The Impact of Mobility as a Service Mode on Transit Access. Mobility as a service as a transit access mode is also referred to as microtransit. Using the microtransit pilot project launched in Salt Lake City, Utah, we applied big data techniques to model the spatio-temporal pattern of microtransit activities. This work is significant as the research period has experienced the impact of COVID-19, and it represents the first of its kind to offer insights into how COVID-19 altered travel behavior. The workflow developed in this research is broadly generalizable and valuable for understanding the unique spatio-temporal patterns of microtransit. The framework can also help transit agencies with performance evaluation, regional transport strategies, and optimal vehicle dispatching.