St John mobilises first responders who volunteer in medical emergencies while an ambulance is on its way, or during more generalised emergencies. For example, St John in Jamaica trains volunteers to assist with car accidents, whereas St John in Scotland supports mountain rescue teams.

Disaster preparedness is an important focus in countries such as Fiji, Mauritius and in the Caribbean. In the past, St John has supported the post tsunami response in Sri Lanka; and provided emergency care to internally displaced people during post-election violence in Kenya and during the attack on Nairobi's Westgate Mall.