Raid Battle

Raid Battles are special, short events that take place within Gyms in Pokémon GO.

Details
A Raid Battle is a cooperative gameplay experience that encourages Trainers to work with other Trainers to defeat an extremely powerful Pokémon known as the Raid Bosses and works as follows:


 * Raid Battles occur only at Pokémon Gyms and might appear between 5:00 AM and 7:45 PM local time; they are then available to battle for 45 minutes (the time window and duration can be changed during particular events).
 * Before a Raid Battle begins, a large Raid Egg will appear atop the Gym with a countdown above it. When the countdown reaches zero, the Raid Boss will be hatched from the Egg (with a new countdown) and can be battled and captured (if defeated) until the countdown runs out.
 * Private Lobbies can be created if desired, which can operate simultaneous to each other and an open lobby. They function otherwise the same as the open lobby.
 * Up to 20 trainers may participate in a raid party (each local player may invite up to 5 players to join via a Remote Raid Pass). Each trainers' Raid Pass is consumed when the raid begins.
 * Upon entering the Raid Lobby, a timer shows how much time there is until the raid begins. Until that point, each player in the lobby may:
 * Modify their team or swap to a preset team
 * Use items (such as to heal their Pokémon)
 * Invite additional players to join via Remote Raid Pass (must be done before the timer reaches 30 seconds)
 * Exit the raid (to avoid losing their Raid Pass if they decide not to attempt the raid).
 * Raid Passes are not refunded for failed raids; however, attempting the same raid after failing will not require an additional Raid Pass, allowing a player to retry for free as much as they like until the raid instance de-spawns.


 * Once the battle begins, the raid party has to defeat the Raid Boss within a time limit (3 minutes for rank 1-4 raids and 5 minutes for rank 5-6 raids) or they fail the raid and must either try again or give up the attempt.


 * Upon successfully defeating the Raid Boss, each player is awarded a number of Premier Balls based on several metrics and then given the opportunity to capture the Pokémon using only those balls and any Berries they have. (Like with Shadow Pokémon, the trainer can not access their regular Pokéball supplies during this catch attempt.)
 * Similar to Rocket Encounters, the reward Pokémon from a raid can be captured until the Gym reverts to normal (thus de-spawning the Pokémon). Usually this is not an issue, but if a player is disconnected from the game during the last minute of the raid or Bonus Challenge, the Pokémon may become unobtainable from that instance if the Gym reverts to normal or spawns a new Raid Egg.

Mega Raid Battles
Mega Raid Battles are a special Raid type that allows Trainer to battle Mega Evolved Pokémon in order to gather large amounts of Mega Energy for that Pokémon. These Raids have a powerful Raid Boss, typically rated as a Tier 4 Raid Boss. The amount of Mega Energy earned is based on how fast the raid is completed (at the cost of replacing the Premier Balls that would normally be earned). In the case of a Legendary Pokémon in a Mega Raid, they are assigned as Tier 6 and as such are exceptionally difficult, often requiring significantly larger raid parties to succeed.

Upon defeat, a Mega Pokémon reverts to its normal form which can then be caught as usual in the Bonus Challenge with a chance of it being shiny.

Primal Raid Battles
Primal Raid Battles are a special Raid type that allows Trainer to battle Pokémon in Primal forms in order to gather large amounts of Primal Energy for that Pokémon. Such as the Mega Raid Battles, these Raids have a powerful Raid Boss, and the amount of Primal Energy earned is based on how fast the raid is completed. Also, upon defeat, the primal Pokémon reverts to its normal form.

Elite Raid Battles
Elite Raid Battles appear from special Raid Eggs that take 24 hours to hatch. Once the Raid Egg has hatched, a Raid Boss appears for 30 minutes. Elite Raid Bosses can only be battled in-person. Trainers will not be able to participate in Elite Raids using Remote Raid Passes.

EX Raid Battles
There were also a special Raid called an EX Raid Battle which was an invitation-only Raid. A Trainer would receive a notification along with time, date and location; along with an EX Raid Pass to gain entry into the Raid.

Raid Passes


Before a Trainer can battle the Raid Boss, they'll need a Raid Pass. Trainers can receive one free Raid Pass per day by visiting a Gym, but can only hold one at a time (some events may increase how many can be obtained per day, but do not increase how many can be held). A Premium Battle Pass may also be purchased from the in-game Shop, which can be used in place of a standard Raid Pass (with no limit to how many may be held). Players can also battle a Raid Boss remotely using a Remote Raid Pass, either jumping into a raid in range or via an invite from a player on their Friend List; up to three Remote Raid Passes may be held at a time.

Raid Boss
A Raid Boss or Boss Pokémon is an extremely powerful Pokémon that has very high CP. It hatches from a egg which appears atop a Gym upon the beginning of the Raid Battle. A countdown will display the time until the egg hatches and the battle begins.

Upon using a Raid Pass to join the battle, the Trainer and up to 19 other Trainers work together to defeat the Raid Boss. If a Raid Boss is successfully defeated within the three-minute time limit, or five-minute time limit for Legendary Raids, those Trainers have the chance to catch that powerful Pokémon for their own. The captured Pokémon does not necessarily have the same moves as the Raid Boss.

A Raid Boss can be battled as many times as possible before it is either defeated or the 45-minute time limit expires.

List of Raid Bosses
There are a limited number of Pokémon that can be possible Raid Bosses at the same time.

The pool of available Raid Boss Pokémon have been changing since the feature release. Additionally, in past events, there have been exclusive Raid Bosses that cannot normally be encountered in Raid Battles. Some Raid Boss Pokémon had even their Tiers changed.

Tiers of Raid Bosses
Tiers are simply difficulty levels of Raid Bosses, distinguished with specific Raid Eggs which hatch into Raid Bosses - Normal, Rare, Legendary, and Mega. Upon the beginning of countdown for the Raid Battle, a Raid Egg will be placed atop the Gym. A countdown will display the time until the Egg hatches and the Raid Battle begins.

A Raid Egg will usually appear one hour before it will hatch. The Raid tab in the Nearby Tab will denote the hatch time in 24-hour clock or military time. Once the Egg hatches, the Raid Boss will become available for battling, usually for the next 45 minutes. The hatch timer may be shorter and the raid availability timer may be longer in events.

Raid Boss CP formula
The formula is identical to the traditional CP Formula; except the stamina and CP scalar portion in the divisor are replaced with a tier scalar which also represents the Raid Boss's HP and the IVs for attack and defense are fixed to 15 (maximum IV).

$${Raid Boss CP = \frac{(Base Atk + 15) ~ \times ~ \sqrt{Base Def + 15} ~ \times ~ \sqrt{TierScalar}}{10}}$$

Where   is:
 * Tier 1:  
 * Tier 2:  
 * Tier 3:  
 * Tier 4 and Mega Raids:  
 * Tier 5:  
 * Elite Raids:  
 * Tier 6 (marked as 5) and Mega Legendary:  

Rewards
Completing a Raid Battle for the first time will always award 1,000 Stardust. After defeating a Raid Boss, Trainers receive a collection of rewards which depend on the Tier of defeated Raid Boss.

Prior to the release of Mega Evolution and Raid Tier associated with it, Tier 1 and Tier 3 Raid Battles only rewarded 3,000 and 4,000 XP respectively. The current XP rewards were formerly given in Tier 2 and Tier 4 Raid Battles. Rare Candy XL can only be rewarded from in-person raids.

Bonus Challenge
Bonus Challenge is a feature available for Trainers who successfully defeated Raid Boss and it gives an opportunity to catch the Raid Boss Pokémon as if it was a Pokémon in the wild, but with a significant difference – Trainer cannot use their owned Poké Balls.

After successfully defeating the Raid Boss and being rewarded with Items, there are Raid Battle performance summary shown to Trainer with amount of Premier Balls given to them and the button displayed.

Initially, the Team Contribution Bonus was rewarding extra Premier Balls, however it was changed with Mega Raids introduction and it is now replaced with Speed Bonus that is time in which Raid Boss was defeated.

Typically Raids Speed Bonus rewards Trainer with additional Premier Balls, while in Mega Raid Battles there is Mega Energy given depending on the Speed Bonus.

After tapping on the Bonus Challenge button, the encounter screen shows up with Pokémon that is a defeated Raid Boss. The player does not have their currently owned Poké Balls for use but only the Premier Balls that they have been rewarded for performance in won Raid Battle.

Pokémon in Bonus Challenge, especially Legendary and Mythical Pokémon, tend to dodge and attack more frequently and have low capture rate. However, the longer the catching attempt goes (ie: fewer Premier Balls remaining) there is an increased catching chance (though the exact amount is still being researched, it appears that as of the 9th ball used it is equivalent to using an Ultra Ball).

If Trainer do not manage to capture the Pokémon with their last Premier Ball and there are no more Premier Balls left, the Pokémon will flee.

Trainer can leave the encounter screen of Bonus Challenge and re-enter it by tapping on the same Gym which the Raid Boss was defeated at, but as long as the Raid still occurs on that Gym.

Trainer can capture Pokémon after defeating Raid Boss in the Raid Battle which has ended and is no longer visible on Gym but once they leave the encounter screen they cannot return to it.

History

 * June, 2017 - Raids were open being available for players level 35 and above.
 * June, 2017 - Raids were made available for players level 31 and above.
 * June, 2017 - Raids were made available for players level 28 and above.
 * June, 2017 - Raids were made available for players level 25 and above.
 * June, 2017 - Raids were made available for players level 20 and above.
 * July, 2017 - Raids were made available for players level 5 and above.
 * August, 2020 - Raids got Tier 2 merged with Tier 1 and Tier 4 merged with Tier 3.

Trivia

 * The Raid Boss icon is based off of Rhydon's face — who was the first Pokémon designed and programmed into the original game. There are also various Rhydon statutes that can be found throughout the game as well.
 * Legendary Raid Bosses have a base capture rate of 2%.
 * Before introduction of Research tasks and Trainer Battles, Rare Candy, Golden Razz Berry and TMs were exclusively available as rewards from Raid Battles.
 * On November, 2017, the Raid Bosses were rotated for the first time.
 * During Pokémon GO Park and Pokémon GO Stadium event in Yokohama, for the first time in game, there were several event-exclusive Raid Boss Pokémon available.
 * Pokémon such as Meowth, Pikachu, Wobbuffet, Ursaring, Houndoom and few others were available as Raid Bosses on 4th Tier level.
 * Originally, the amount of Stardust given per Raid Battle was 500. It was increased to 750 on October, 2018. Then it was increased to 1000 on January , 2019.
 * Before January, 2019, the stamina of Tier 3 to 6 Raid Bosses were 3,000, 7,500, 12,500 and 18,750 respectively.
 * Prior to the release of Mega Evolution and the Raid Tier associated with it, there were common Tier 2 and Tier 4 Raid Battles. They were merged with Tier 1 and Tier 3 Raids respectively.
 * Before the A Mega Moment update on April, 2022, the stamina of Mega Raid Bosses were same as Tier 5. It is now Tier 4 stamina.
 * Mega, Ultra Beast and Elite Raids did not count towards the "Win a three-star raid or higher" research task. This was fixed around November 2022.
 * Mewtwo in normal Raid Battle and Darkrai in Halloween 2019 are the only Tier 6 Raid Bosses, with buffed HP and CP. They are labelled as Tier 5 in the game and give the same awards upon victory.
 * Raid Battle concept was adapted in Pokémon Sword and Pokémon Shield games. They are called Max Raid Battles and they are source of obtaining Gigantamax Pokémon.