The COVID-19 pandemic is a time of high uncertainty which has induced feelings of job insecurity among employees. Previous research shows that job insecurity results in severe negative consequences for both employees and organisations. The present study therefore aimed to investigate whether employees take personal proactive action to mitigate feelings of job insecurity and its associated negative outcomes. Specifically, it investigated whether quantitative and/or qualitative job insecurity influence job crafting (i.e., seeking resources and seeking challenges), and whether self-efficacy moderates these relationships. These relationships were investigated at both between- and within-person levels using a 10-day diary study design. 56 full-time employees from a range of industries in New Zealand completed a baseline survey and 10 short daily surveys. The multilevel regression found no significant within-person relationships, although there were daily fluctuations in job insecurity and job crafting. However, between-person results showed higher levels of job insecurity were related to less job crafting behaviour. Quantitative job insecurity predicted less resource-seeking, and qualitative job insecurity predicted less challenge-seeking and less overall job crafting. Contrary to expectations, self-efficacy did not moderate any of these relationships. These results suggest that, instead of engaging in proactive behaviour, job-insecure participants withdraw from work and become uninvolved. Job insecurity may trigger protective behaviour that is used as an attempt to cope and reduce job insecurity’s negative impact. This has implications for organisations who can take action to increase positive outcomes and reduce withdrawal behaviour.