Season 12

Season 12 of GO Battle League, also called GO Battle League: Season of Light, lasted from September, 2022 to December , 2022. It is preceded by Season 11 and succeeded by Season 13. This GO Battle League Season ran concurrently with Season of Light.

Formats
Little Jungle Cup Remix: 500 CP limit. Only Normal-, Grass-, Electric-, Poison-, Ground-, Flying-, Bug-, and Dark-types allowed. Shuckle, Smeargle, Skorupi, Cottonee, Ducklett, and Salandit are banned.

Psychic Cup: 1,500 CP limit. Only Psychic-types allowed. Mew is banned.

Weather Cup: 2,500 CP limit. Only Fire-, Water-, Ice-, and Rock-types allowed.

Evolution Cup: 1,500 CP limit. Only Pokémon that have evolved at least once and can evolve again allowed.

Halloween Cup: 1,500 CP limit. Only Poison-, Bug-, Ghost-, Dark-, and Fairy-types allowed.

Halloween Cup: Ultra League Edition: 2,500 CP limit. Only Poison-, Bug-, Ghost-, Dark-, and Fairy-types allowed.

Willpower Cup: 1,500 CP limit. Only Fighting-, Psychic-, and Dark-types allowed. Gardevoir is banned.

Ultra Premier: 2,500 CP limit. Legendary Pokémon, Mythical Pokémon, and Ultra Beasts are banned.

Ultra Premier Classic: 2,500 CP limit. Legendary Pokémon, Mythical Pokémon, Ultra Beasts, and Pokémon that have been powered up with Candy XL are banned.

Master Premier Classic: No CP limit. Legendary Pokémon, Mythical Pokémon, Ultra Beasts, and Pokémon that have been powered up with Candy XL are banned.

Element Cup Remix: 500 CP limit. Only Fire-, Water-, and Grass-types allowed. Only Pokémon that are able to evolve and have not evolved even once are allowed. Chinchou, Cottonee, Ducklett, and Salandit are banned.

Catch Cup: Season of Light Edition: 1,500 CP limit. Only Pokémon caught during the Season of Light allowed.

Rewards
Basic Premium

Stardust The random items can include:
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Reaching Ace rank and above awarded avatar items inspired by Guzma.

Guzma-Style Wristbands could also be obtained from GO Battle Day rewards.

Pokémon
Guaranteed first Pokémon encounters:
 * Pinsir: rank 1 (one only)
 * Mienfoo: rank 6
 * Axew: Ace rank
 * Noibat: Veteran rank
 * Goomy: Expert rank
 * Pikachu Libre: Legend rank (one only)

Certain Legendary Pokémon, Mythical Pokémon, and Ultra Beasts could be obtained starting at rank 20 during their time in tier 5 Raid Battles.

End-of-season rewards

 * (rank 19 or above)

Timed Research
GO Battle League Timed Research is a Timed Research for Season of Light and the GO Battle League Season 12. A Ticket for this Timed Research was available in the in-game shop at no cost. Each part of the Timed Research had the same requirements, with the only difference being the rewards for completing each part.

GO Battle Day: Guzma
GO Battle Day: Guzma took place on October, 2022 from 12 a.m. to 11:59 p.m. local time. Master League and Master Premier Classic were available during this GO Battle Day. Stardust from completing sets would not be counted for the bonus.

GO Battle Day: Miltank
GO Battle Day: Miltank took place on November, 2022 from 12 a.m. to 11:59 p.m. local time. Ultra League and Willpower Cup were available during this GO Battle Day. Stardust from completing sets would not be counted for the bonus.

Attack Updates
At the start of this Season, certain Attacks had their stats changed, certain Pokémon received updates to their obtainable Attacks, and new Attacks were added.

Attack Changes

 * Zap Cannon: Chance to decrease the opponent's Attack by 1 stage decreased from 100% to 66% in Trainer Battles.
 * Icicle Spear: Energy cost increased from 35 to 40 in Trainer Battles.
 * Rollout: Energy gain decreased from 14 to 13 in Trainer Battles.
 * Ancient Power: Base power increased from 45 to 60 and 10% chance to increase the user's Attack and Defense by 2 stages decreased to 1 stage in Trainer Battles.
 * Ominous Wind: 10% chance to increase the user's Attack and Defense by 2 stages decreased to 1 stage in Trainer Battles.
 * Silver Wind: Base power increased from 45 to 60 and 10% chance to increase the user's Attack and Defense by 2 stages decreased to 1 stage in Trainer Battles.
 * Quick Attack: Energy gain increased from 7 to 8 in Trainer Battles.
 * Tackle: Energy gain increased from 2 to 3 in Trainer Battles.

Attack Availability Updates
Some Pokémon received updates to their obtainable Attacks. These were added to their standard Attack pools.

Trivia

 * For a short time after the Season 12 Attack updates went live, Ancient Power and Silver Wind gave the user energy upon use, instead of using energy.
 * Double Kick was also added to Cobalion, Terrakion, and Virizion at the start of the season, despite not being listed in the announcement blog post.