Flexible work arrangements, such as teleworking, are increasingly being offered by organizations, yet availability does not necessarily translate into employee utilization. Understanding the factors that influence their effective and actual use has, therefore, become essential. This study examines the relationship between employees' availability to flexplace and their subsequent use of it, controlling for baseline use. Specifically, we test whether the two facets of workplace Fear of Missing Out (wFoMO), informational and relational, moderate this relation. Using a three-wave, time-lagged design with 99 employees (employees' availability to flexplace measured at T1, wFoMO at T2, and use of flexplace at T3), we estimated a structural equation model. Consistent with our hypothesis, the informational dimension of wFoMO significantly weakened the positive association between employees' access to flexible work and their subsequent use. Worries about missing important updates or knowledge made employees less likely to turn flexible work access into actual use. The relational dimension was not significant. These findings highlight the importance of psychological factors in shaping the effectiveness of organizational flexibility policies and suggest strategies to support employees in leveraging available work options. We discuss implications on proactive flexibility practice, emphasizing the need for information-management routines (e.g., reliable asynchronous updates) to mitigate informational wFOMO and enable employees to take advantage of flexible work options.