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.

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
 * Rank 5: Mysterious Item
 * Rank 10: 750 (Basic) / 1500 (Premium) Stardust
 * Rank 15: 1 (Basic) / 2 (Premium) Rare Candy
 * Rank 19: Pokémon Encounter
 * Other ranks:

Stardust

The random items can include:
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Reaching rank 19 awarded:

Reaching Ace rank and above awarded avatar items and an avatar pose inspired by Guzma from Pokémon Sun and Moon.

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)

Tier 5 Raid Bosses could be obtained starting at rank 20 during their time in raids.

End-of-Season rewards

 * (rank 19 or above)

Timed Research
GO Battle League Timed Research is 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.

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.

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

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
Some Pokémon received new Attacks 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 initially being listed in the announcement blog post.