Season 4

Season 4 of GO Battle League lasted from September, 2020 to November , 2020. It is preceded by Season 3 and succeeded by Season 5.

GO Battle Night occurred during this Season on November, featuring new format – Flying Cup, in which only Flying-type Pokémon were allowed.

During this Season, Trainers still did not require walking to unlock battle sets.

Formats
Halloween Cup: 1,500 CP limit. Only Poison-, Ghost-, Bug-, Dark-, and Fairy-type Pokémon allowed, excluding Legendary and Mythical ones.

Flying Cup: 1,500 CP limit. Only Flying-type Pokémon allowed.

Ranks and Ratings
Rank 8 and 9 could be reached by winning certain amount of battles rather than reaching the set ratings. Rating was only shown after reaching rank 9.

Rewards
Basic Premium

Stardust

The random items can include:
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Reaching rank 10 awarded avatar items and an avatar pose inspired by Blue and Poké Ball Show-Of pose.

Pokémon
Guaranteed first Pokémon encounters:
 * Pidgeot: rank 1
 * Galarian Zigzagoon: rank 4
 * Galarian Farfetch'd: rank 7
 * Rufflet: rank 8
 * Scraggy: rank 9
 * Pikachu Libre: rank 10 (one only)

Halloween-costumed Kanto Starters were only available during Halloween Cup.

End-of-Season rewards

 * (rank 7 or above)

GO Battle Night
The first GO Battle Night took place on November, 2020 from 6 p.m. to 11:59 p.m. local time. Flying Cup would run, which only allows Flying-type Pokémon with a CP Limit of 1,500. All other Leagues were also available during GO Battle Night, including Ultra Premier Cup.

In order to obtain Gust, Trainers had to evolve Pidgeotto into Pidgeot during the event. Trainers cannot use TMs to obtain the attack.

Attack updates
These Attack updates went live at the start of the Season:

Attack changes

 * Bug Buzz: 30% chance to decrease the opponent's Defense by 1 stage in Trainer Battles.
 * Flame Charge: Base power decreased from 70 to 65 and 100% chance to increase the user's Attack by 1 stage in Trainer Battles.
 * Signal Beam: 20% chance to decrease the opponent's Attack and Defense by 1 stage in Trainer Battles.

Attack availability
Some Pokémon received new Attacks to their standard Attack pools:

Events

 * Due to serious connection problems since the start of this Season, the GO Battle Night originally planned on September was postponed.
 * On October, the rescheduled time of GO Battle Night was announced to be November 6 p.m. to 11:59 p.m. local time.