Smartphones, with their ubiquitous presence, have become indispensable devices. Considerable research has been conducted on the pros and cons of mobile availability, but comparatively less research exists on different forms of mobile unavailability. Using an online factorial survey on 146 German smartphone users, the situational, usage-related, and personality-related factors influencing the perception of 72 systematically constructed fictitious scenarios of mobile unavailability were studied. Using a multilevel approach, the research revealed that the place, reason and duration of unavailability, and expectation of contact attempts influence situational mobile unavailability. Individual factors such as the significance of mobile availability, the availability expectations of friends, a disposition for FOMO (fear of missing out), and a high level of conscientiousness influence the perception of the unavailability scenarios. Furthermore, three cross-level effects between situational and individual factors are found.