Purpose: The purpose of this study is to explore open data portals as data literacy learning environments. The authors examined the obstacles faced and strategies used by university students as non-expert open data portal users with different levels of data literacy, to inform the design of portals intended to scaffold informal and situated learning. Design/methodology/approach: The authors conducted an observational user study, in which 14 student participants grouped by self-reported data literacy measures carried out assigned tasks in an open data portal. Data were collected through screen capture, think-aloud protocols and post-session interviews. Findings: Participants experienced numerous challenges in finding and using data, with some variation shown between the different literacy groups. The higher data literacy group primarily faced challenges using unfamiliar tools, which may be addressed by improving system usability, while the lower data literacy group struggled due to gaps in basic understanding, which may be addressed by increasing point of need instruction and guidance. Participants used several learning strategies but primarily relied upon trial and error, which was less effective for low data literacy users. Originality/value: This study is unique in comparing open data portal use among adult students across data literacy levels through an empirical user study. It contributes methodologically by proposing an instrument for data literacy assessment. It offers a novel perspective on information systems as sites for informal learning and skills development, beyond the immediate goals of system use, and offers concrete suggestions for the future design of open data portals for students and non-expert, citizen users.