Objectives: Since their introduction in 2019, the use of e-scooters has become widespread in Germany. Concerns about road safety, especially pedestrian safety, have arisen as the popularity of micro-mobility has grown. In light of this context, the present study investigates which types of road infrastructure e-scooter riders use, with a focus on riding on the sidewalk, which is not permitted in Germany. We considered the following infrastructures: (1) off-road bike lane (+ sidewalk and road), (2) on-road bike lane (+ sidewalk and road), and (3) road (+ sidewalk). Methods: Observations at six sites (recording 738 e-scooter riders) and on-site surveys (involving responses from 129 e-scooter riders) were conducted in two German cities in August 2020 and September 2020. Results: Self-reported sidewalk riding was not found to be linked directly to a lack of rule knowledge, a preference for this type of infrastructure, or perceived safety. Observations indicated that using the sidewalk might be related to situational components, such as comfort or convenience, comprising up to 40% of instances of sidewalk riding. Conclusion: Considering the comfort and convenience factor of sites when building or improving cycling infrastructure can help keep e-scooter riders from riding on the sidewalk.