Background: Previous eBook studies were primarily cross-sectional surveys or experimental studies providing a snapshot of the impact of eBook reading on children's emergent literacy skills. Scholars have yet to characterize more fine grain developmental progressions in the use of eReaders and similar devices -- that is, how children's eBook-related practices evolve over time and what might be changing behaviourally over the course of repeated readings for any age group. Objectives: This is the first study to characterize young children's (2 to 3 years) use of eReaders over the span of several months under semi-naturalistic conditions. Methods: Twenty five mothers and their 2.5- to 3.5-year-old child engaged in a series of documentation exercises and interviews around use of a novel eReader device. This study is exploratory and deductive in nature, and hypotheses were not set forth a priori. Results and Conclusions: The results of the present study suggest that children develop increasing mastery of the affordances of eReaders as their device exposure increases. Over time, their ability to independently engage with devices rapidly increases. They transition from needing technical support from parents and high levels of encouragement to attend to literacy content over hotspots, to sometimes using the device independently, to considering the device a mainstay in their home -- no longer a novelty. Implications for practice and/or policy: The developmental usability patterns noted in this study extend our naturalistic understanding of young children's dexterity with digital devices and point to methodological approaches that might yield more ecologically valid findings in future studies.