Introduction - During spring 2020, four regions of France faced a surge of severe COVID-19 patients which threatened to overflow local intensive care units (ICU) capacities. As an emergency response, between 13 March 2020 and 10 April 2020, an estimated 661 patients were transferred from overcrowded ICUs to eight other French regions and four neighbouring countries. The intensity, geographical spread and the diversity of vectors used are unprecedented. The study aims at assessing the impact of these inter-ICU transfers on the short-term and medium-term physical and psychological outcomes in this population of severe COVID-19 patients. Methods and analysis - The TRANSCOV cohort is a multicentre observational retrospective study. All transferred patients between ICUs outside the origin region will be invited to take part. For each transfer, up to four control patients will be selected among those admitted in the same ICU during the same period (±4 days of transfer date). Clinical data will be extracted from medical records and will include haemodynamic and respiratory parameters, as well as clinical severity scores before, during and after transfer. Data linkage with medicoadministrative data will enrich the clinical database and allow follow-up up to 1 year after initial admission. Ethics and dissemination - The study has been approved by the French Ethics and Scientific Committee on the 16 July 2020 (file no. 2046524). The results will be disseminated via publication of scientific articles and communications in national and international conferences. Trial registration number - 20 CO 015 CZ.