In the spring term 2020, students faced a sudden change from on-campus learning to online learning with synchronous and asynchronous online courses. To study successfully, students not only needed to be prepared in terms of digital readiness, they also faced challenges that pertained to the self-regulated management of external resources. In the current study, we investigated students’ digital readiness for the sudden switch to online learning (workspace, equipment, previous experiences, and information sharing behavior); differences between their intended and actual use of external resource management strategies (environment structuring, time management, and help-seeking); and the influence of students’ digital readiness on their actual use of resource management strategies. Students enrolled in a full-scale, German university (N = 662) answered two online questionnaires (before and in the middle of the term). Results indicate that students seemed to be ready to study online but were not able to manage their resources during the term as frequently as intended. Finally, different indicators of students’ digital readiness revealed connections to different types of resource management strategies. Based on the current results, we discuss implications for the promotion of student self-regulated learning in online emergency remote teaching based on both external resources and digital readiness.