Season 17

Season 17 of GO Battle League, also called GO Battle League: Timeless Travels, lasts from December, 2023 to March , 2024. It is preceded by Season 16 and will be succeeded by Season 18. This GO Battle League Season runs concurrently with Timeless Travels.

Formats
Retro Cup: Great League Edition: 1,500 CP limit. Dark-, Steel-, and Fairy-types are banned.

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

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

Fantasy Cup: Great League Edition: 1,500 CP limit. Only Dragon-, Steel-, and Fairy-types allowed.

Evolution Cup: Great League Edition: 1,500 CP limit.

Hisui Cup: Great League Edition: 1,500 CP limit. Only Pokémon found in the Pokémon Legends: Arceus Pokédex allowed.

Great League Remix: 1,500 CP limit. Alolan Sandslash, Alolan Ninetales, Wigglytuff, Noctowl, Lanturn, Azumarill, Umbreon, Pelipper, Sableye, Medicham, Altaria, Registeel, Defense Forme Deoxys, Bastiodon, Toxicroak, Scrafty, Galarian Stunfisk, Greninja, Talonflame, and Trevenant are banned.

Catch Cup: Great League Edition: 1,500 CP limit. Only Pokémon caught during Timeless Travels allowed.

Catch Cup: Little Edition: 500 CP limit. Only Pokémon caught during Timeless Travels 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 Ingo from Pokémon Legends: Arceus.

Ingo-Style Hat (Hisui) could also be obtained from GO Battle Day rewards.

Pokémon
Guaranteed first Pokémon encounters:
 * Hisuian Sneasel: rank 1 (one only)
 * Machoke: rank 6 (one only)
 * Deino: Ace rank
 * Goomy: Veteran rank
 * Jangmo-o: 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 the GO Battle League Season 17. A Ticket for this Timed Research was available in the in-game shop at no cost from December, 2023, at 1:00 p.m. PDT to December , 2023, at 1:00 p.m. PDT. Each part of the Timed Research had the same requirements, with the only difference being the rewards for completing each part.

GO Battle Week: Timeless Travels
GO Battle Week: Timeless Travels took place from January, 2024, 10:00 a.m. local time to , 2024, 8:00 p.m. local time. Great League, Ultra League, and Master League were available during this GO Battle Week.

Timeless Travels: GO Battle Day
Timeless Travels: GO Battle Day took place on February, 2024, from 12 a.m. local time to 11:59 p.m. local time. Master League and Evolution Cup: Great League Edition were available during this GO Battle Day.

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

Attack changes

 * Mud-Slap: Energy gain increased from 8 to 9 in Trainer Battles.
 * Fire Spin: Base power increased from 9 to 10 in Trainer Battles.
 * Incinerate: Base power increased from 15 to 20 in Trainer Battles.
 * Blaze Kick: Base power increased from 55 to 60 in Trainer Battles.
 * Breaking Swipe: Chance to decrease the opponent's Attack decreased from 100% to 50% in Trainer Battles.
 * Iron Tail: Base power increased from 9 to 10 and energy gain increased from 6 to 7 in Trainer Battles.
 * Steel Wing: Energy gain increased from 5 to 7 in Trainer Battles.
 * Astonish: Base power increased from 5 to 9 in Trainer Battles.
 * Bubble: Base power increased from 7 to 8 in Trainer Battles.
 * Scald: Base power increased from 80 to 85 and chance to decrease the opponent's Attack increased from 30% to 50% in Trainer Battles.
 * Psychic: Base power decreased from 85 to 75 in Trainer Battles.

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

Trivia

 * There were some errors in the announcement blog post. These included:
 * Icy Wind was also added to Baxcalibur, despite not being listed.
 * Palossand could already learn Astonish.
 * Nymble and Lokix could already learn Trailblaze.
 * White and Black Kyurem were accidentally released as GO Battle League rewards during Kyurem rotation in December 2023.