Objectives Severe necrotising soft tissue infections (NSTI) are rare life threatening rapidly progressing bacterial infections requiring immediate diagnosis and treatment. The aim of the study was to explore the experience of family caregivers of patients with necrotising soft tissue infection during the acute stage of disease. Methods Our study had a qualitative descriptive binational design using qualitative content analysis to explore diaries written by close family members (n=15). Participants were recruited from university hospitals in Denmark and Sweden. Findings Three main categories emerged: Trajectory, Treatment, and Patient & Family. The first helped us construct an overview of the NSTI trajectory showing issues of importance to patient and family caregivers. The following categories were analysed further to describe four themes central to the family caregiver experience: craving information, needing to be near, suffering separation and network taking over. Conclusions Necrotising soft tissue infections are uncommon causing shock and concern. Centralised treatment might involve physical separation of patient and family during the acute stage of illness. Family accommodations near the patient and accessibility to adequate communication devices at the bedside are recommended. Health professionals need to keep in mind the importance of information and reassurance on the wellbeing of the family and ultimately of the patient.