EX Raid Battles are similar to existing Raid Battles, with a few notable differences. EX raids will periodically appear at Gyms around the world; however, unlike existing raids, Trainers will be invited to join an EX Raid Battle. To receive an invitation to participate in an EX Raid Battle, Trainers must have successfully completed a raid recently, by defeating the Raid Boss, at the Gym where the EX Raid Battle will be taking place. The invitations will include advance warning of when the EX Raid will take place, giving them ample time to coordinate with other Trainers before taking on the powerful Raid Boss.
The eligibility requirements for an EX Raid Battle are the following: frequency, times, locations, and duration of a Raid Battle. These factors will increase a Trainer's chance of being invited to an EX Raid Battle.