The Wales Air Ambulance Charitable Trust (Welsh: Ymddiriedolaeth Elusennol Ambiwlans Awyr Cymru), also known as Wales Air Ambulance Charity (WAAC; Welsh: Elusen Ambiwlans Awyr Cymru, EAAC), is a charity air ambulance service providing a free, life-saving helicopter emergency medical service (HEMS) for the critically ill and injured in Wales. It is an independent charity that relies on charitable donations to supply and maintain a fleet of emergency aircraft and rapid response vehicles.