To participate in Legendary Raid battles in Pokémon GO, you need special passes that are only distributed to very active gym players.
New insights into the Legendary monsters in Pokémon GO from the latest data mining: These will for example find their way into the game during Legendary Raid battles and will utilize the new raid system. (Whether this is the only way to encounter the legendary Pokémon is unclear.)
To participate in such a legendary raid battle, you need a special raid pass, which is only distributed to the most active players worldwide.
Legendary Raid Pass
According to the latest information from data mining of Patch 0.67.1, not every trainer can participate in Legendary Raid battles, but only a limited portion of the community. As a prerequisite for these battles, you must possess a Legendary Raid Pass.
You can carry these accesses for Legendary Raid battles simultaneously with another raid pass. They do not count towards the limit of raid passes.
How to get a Legendary Raid Pass?
These special passes for raids featuring legendary Pokémon are not simply distributed to everyone, but only to a special group of players. Niantic explains how this is supposed to work: The passes (possibly also passwords) are given to trainers who have been particularly active in the gym system. They then have the chance to catch a legendary Pokémon later.
At this point, it is unclear whether trainers will receive passwords or Legendary Raid Passes to participate in these special battles. You should definitely have access to the email account linked to your Pokémon GO account. It is also unclear what “particularly active” means in this context. Presumably, Niantic will provide more detailed statements about this in the coming days.
At the same time, this means that you should not feel pressured to attend Pokémon events such as the Pokémon Fest. Archit Bhargava, marketing lead at Niantic, told Massivelyop.com that these events are intended to connect players with similar interests. There will not be a unique chance to catch Mewtwo at these events.
Rewards for Legendary Raid Battles
The code of Pokémon GO has already revealed the possible rewards for the battles against legendary Pokémon. Trainers who participate in and win these battles will receive these special Lugia badges.
The badges come in three categories: bronze, silver, and gold, and likely indicate how many battles you have winned against legendary monsters (not how many you have participated in). It is possible that you will need to battle a legendary Pokémon multiple times before you can successfully catch it.
It is currently unclear how many Legendary Raid battles must be won to receive the bronze, silver, or gold badge. It is assumed that the numbers are rather low (Bronze 1-4, Silver 5-9, Gold from 10).
Legendary Raid Eggs at the Gyms
A Legendary Raid boss announces itself before spawning through a special raid egg and a notification in the game. At this egg, you can tell that a legendary opponent is waiting in the gym when the countdown next to it has expired.
The battles against legendary Pokémon then proceed according to similar rules as the raid battles. On this topic, we have a special guide for you that covers various aspects of raids. Raid battles, levels, bosses, and attacks – What are raids in Pokémon GO
Pokémon GO Gym Guide: Everything about battles, badges, and Pokémon motivation can be read here


