COVID-19 was a challenge for health-care systems worldwide, causing large numbers of hospitalizations and inter-hospital transfers. We studied whether transfer, as well as its reason, was associated with the duration of hospitalization in non-ICU and ICU patients. For this purpose, all patients hospitalized due to COVID-19 between August 1st and December 31st, 2021, in a network of hospitals in Southern Germany were comprehensively characterized regarding their clinical course, therapy, complications, transfers, reasons for transfer, involved levels of care, total period of hospitalization and in-hospital mortality, using univariate and multiple regression analyses. While mortality was not significantly associated with transfer, the period of hospitalization was. In non-ICU patients (n = 545), median (quartiles) time was 7.0 (4.0–11.0) in non-transferred (n = 458) and 18.0 (11.0–29.0) days in transferred (n = 87) patients (p < 0.001). In ICU patients (n = 100 transferred, n = 115 non-transferred) it was 12.0 (8.3–18.0) and 22.0 (15.0–34.0) days (p < 0.001). Beyond ECMO therapy (4.5%), reasons for transfer were medical (33.2%) or capacity (61.9%) reasons, with medical/capacity reasons in 32/49 of non-ICU and 21/74 of ICU patients. Thus, the transfer of COVID-19 patients between hospitals was associated with longer periods of hospitalization, corresponding to greater health care utilization, for which specific patient characteristics and clinical decisions played a role.