Season 13

Season 13 of GO Battle League, also called GO Battle League: Mythical Wishes, lasts from December, 2022 to March , 2023. It is preceded by Season 12 and succeeded by Season 14. This GO Battle League Season ran concurrently with Season 9: Mythical Wishes.

Formats
Great League Remix: 1,500 CP limit. Alolan Ninetales, Altaria, Azumarill, Bastiodon, Defense Deoxys, Galarian Stunfisk, Lanturn, Lickitung, Medicham, Nidoqueen, Registeel, Sableye, Scrafty, Skarmory, Swampert, Talonflame, Trevenant, Umbreon, Venusaur and Walrein are banned.

Master League: Mega Edition: No CP limit. Mega-Evolved Pokémon are allowed.

Fighting Cup: GL Edition Remix: 1,500 CP limit. Only Fighting-types allowed, Psychic-type Pokémon are not eligible. Buzzwole, Hakamo-o, Kommo-o and Sneasler are banned.

Holiday Cup: GL Edition: 1,500 CP limit. Only Electric-, Flying-, Ghost-, Grass-, Ice- and Normal-types allowed.

Holiday Cup: UL Edition: 2,500 CP limit. Only Electric-, Flying-, Ghost-, Grass-, Ice- and Normal-types allowed.

Weather Cup: GL Edition: 1,500 CP limit. Only Fire-, Ice-,  Rock- and Water-types allowed.

Electric Cup: GL Edition: 1,500 CP limit. Only Electric-types allowed. Stunfisk, Helioptile, Charjabug, and Vikavolt are banned.

Love Cup: GL Edition: 1,500 CP limit. See official blog post for allowed Pokémon.

Hoenn Cup: GL Edition: 1,500 CP limit. Only Pokémon with a Pokédex number from #252 to #386 are allowed. Galarian Zigzagoon and Galarian Linoone are banned.

Rewards
Basic Premium

Stardust The random items can include:
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Reaching Ace rank and above awarded avatar items inspired by Steven Stone from Pokémon Ruby and Sapphire.

Steven-Style Rings (Ruby/Sapphire) could also be obtained from GO Battle Day rewards.

Pokémon
Guaranteed first Pokémon encounters:
 * Metang: rank 1 (one only)
 * Mareanie: 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 13. A Ticket for this Timed Research was available in the in-game shop at no cost. This research was automatically added to players who had the ticket in Season 12. Each part of the Timed Research had the same requirements, with the only difference being the rewards for completing each part.

GO Battle Weekend: Steven Stone
GO Battle Weekend: Steven Stone took place from January, 2023, 12 a.m. local time to January , 2023, 11:59 p.m. local time. Great League, Ultra League, and Master League were available during this GO Battle Day. Stardust from completing sets would not be counted for the bonus.

GO Battle Day: Vulpix
GO Battle Day: Vulpix took place on February, 2023 from 12 a.m. to 11:59 p.m. local time. Ultra League and Love Cup were available during this GO Battle Day. Stardust from completing sets would not be counted for the bonus.

In order to obtain Ember, Trainers had to evolve Vulpix into Ninetales during the event from 11 a.m. to 2 p.m. Trainers cannot use TMs to obtain the attack.

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

Attack Changes

 * Wing Attack: Energy gain increased from 7 to 8 in Trainer Battles.
 * Poison Fang: Energy cost increased from 35 to 40 in Trainer Battles.
 * Charm: Base power decreased from 16 to 15 in Trainer Battles.

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

Trivia

 * There were some unannounced Attack changes that were not listed in the announcement blog post. These included:
 * Ember was added to Pyroar.
 * Poltergeist was added to Dusknoir.
 * Due to a bug that let multiple Mega Evolved and Primal Reverted Pokémon be used in the same battle team, Master League: Mega Edition was replaced by the standard Master League on February, 2023.