Healthcare must rapidly and systematically learn from earlier COVID-19 responses to prepare for future crises. This is critical for VA's Mental Health Residential Rehabilitation and Treatment Programs (RRTPs), offering 24/7 care to Veterans for behavioral health and/or homelessness. We adapted the World Health Organization's After Action Review (AAR) to conduct semi-structured small-group discussions with staff from two RRTPs and Veterans who received RRTP care during COVID-19, to examine COVID-19's impact on these programs. Six thematic categories emerged through qualitative analysis (participant-checked and contextualized with additional input from program leadership), representing participants' recommendations including: Keep RRTPs open (especially when alternative programs are inaccessible), convey reasons for COVID-19 precautions and programming changes to Veterans, separate recovery-oriented programming from COVID-19-related information-sharing, ensure Wi-Fi availability for telehealth and communication, provide technology training during orientation, and establish safe procedures for off-site appointments. AAR is easily applicable for organizations to debrief and learn from past experiences.