Early Detection and Rapid Response (EDRR) systems are the first line of defence against invasive species once they have penetrated national or inter-island biosecurity systems. For these systems to be effective, a plan is required to coordinate the responsible agencies and ensure both the systems and equipment to address the detected species are in place prior to the response. Several countries have developed these plans recently, which are available on the Battler Resource Base. SPREP thanks James Stanford, who drafted the text for this guide.