The aim of this study was to examine post-traumatic stress disorder (PTSD) symptom levels and coping strategies during the COVID-19 pandemic among treatment-seeking veterans with pre-existing PTSD. A cohort of 176 male treatment-seeking veterans with pre-existing PTSD during the first COVID-19 pandemic lockdown (T1) and 132 participants from the same cohort one year after the onset of the pandemic (T2) participated in a longitudinal study. All participants responded to a COVID-19-related questionnaire and the following measures: the Life Events Checklist for DSM-5 (LEC-5), PTSD Checklist for DSM-5 (PCL-5) and the Brief COPE. The intensity of overall PTSD symptoms, avoidance symptoms and negative alterations in cognitions and mood was lower at T2. PTSD symptoms were not significantly correlated with SARS-CoV-2 potentially traumatic events (PTE) at T2. Veterans scored higher on emotion-focused and problem-focused coping than on dysfunctional coping. Veterans with pre-existing PTSD who were receiving long-term treatment coped with COVID-19 stressors without the effects of retraumatization and a consequent worsening of PTSD symptoms.