Hypercoagulation is central to the pathogenesis of acute and post-acute COVID-19. This prospective observational study explored whether rotational thromboelastometry (ROTEM), a method that unveils coagulation status, predicts outcomes of hospitalized patients with COVID-19 pneumonia. We investigated 62 patients using ROTEM that was conducted at enrollment, clinical deterioration, discharge and follow-up visits 1 and 3 months post-discharge. A hypercoagulable ROTEM was more common at clinical deterioration than at enrollment and the levels of hypercoagulable ROTEM indices correlated with the clinical severity score. Hypercoagulable ROTEM at enrollment was not associated with in-hospital death. Patients with hypercoagulable ROTEM at enrollment, discharge and 1 month post-discharge had an increased risk of persistent symptoms 1 and 3 months after discharge. Patients with hypercoagulable ROTEM at enrollment, discharge, and 1 month after discharge were more likely to have lung diffusion capacity (DLco) impairment 3 months after discharge. High levels of hypercoagulable ROTEM indices were associated with the increased risk of persistent symptoms at later stages of the disease. In a multivariate analysis, (i) hypercoagulable ROTEM at discharge and female gender were linked to the presence of symptoms at one month post-discharge, (ii) hypercoagulable ROTEM at one month after discharge was linked to the presence of symptoms at three months post-discharge, (iii) hypercoagulable ROTEM at enrollment and at discharge and female gender were linked to the presence of impaired DLco at three months post-discharge. Excessive coagulation may contribute to long-COVID pathogenesis and ROTEM findings during hospitalization may predict post-acute-COVID-19 sequelae in patients with COVID-19-related pneumonia.