Many acute and subacute complications of coronavirus disease 2019 (COVID-19) have been reported. However, the recovery process in severely ill patients is not clear. Here, we report three patients with favorable physical function after severe COVID-19. All three patients were older than 65 years and had comorbidities such as diabetes mellitus, hypertension, and smoking habits. During respiratory failure, they received mechanical ventilation support for more than 4 days. Two patients had undergone tracheostomy, and one had undergone extracorporeal membrane oxygenation (ECMO). At the time of transfer to our hospital, they had lower-limb muscle weakness, respiratory distress on exertion, exercise-induced hypoxemia (EIH), and complications from immobility, such as peroneal nerve palsy. During rehabilitation, we monitored peripheral blood oxygen saturation, adjusted the workload, and administered temporary orthotic therapy. The patients improved within 150 days after the onset of the disease, and they were discharged home and were able to walk as a practical means of transportation. Even after severe COVID-19, the patients achieved good physical function. Interventions for EIH and complications due to immobility were additionally necessary. In the future, we must examine the relationship between improvements in physical function and rehabilitation.