With a series as immensely popular and long-running as Pokémon, it's inevitable that several leaks would spring up. These leaks can range from small, vague reveals to full-blown leaks of entire games.
Note that leaks for earlier generations (Generations I-IV) reveal their beta content, with much of said content coming from a massive breach
of Nintendo's servers in 2018.
In General
- Prior to Generation VIII, "hidden" event-exclusive Olympus Mons were discovered almost immediately after their debut games' release via datamining, such as Hoopa from X and Y and Marshadow from Sun and Moon. The tradition was killed off following the release of Sword and Shield, which introduced event-exclusive Pokémon via software updates rather than having them buried within the data.
- While not a problem exclusive to the franchise, starting with Sun and Moon, an unofficial tradition began of mainline releases having their ROM dumps leaked and datamined around a week before their launch.
- Pokémon Red and Green saw a handful of backsprites for unused Pokémon make it into public circulation in February 2019. There was some notable controversy over this leak, as a fansite known as Helix Chamber created a ROM Hack with mockups of said Pokémon's front sprites while passing it off as a genuine prototype.
- Pokémon Gold and Silver had two prototype versions leaked:
- The Spaceworld 1997 demo got leaked in 2018. The game came out in 1999, so of course no new features were revealed, but there's plenty of very interesting things regardless; There's a lot of unused beta Pokémon that were discarded, some of which have become popular and have fans demanding they be made official Pokémon, and alternate prototype versions of existing Pokémon, among other cut features.
- In April of 2020, the Spaceworld 1999 demo was leaked to the public. It was significantly closer to the final product than the '97 demo, but it still contained several removed features. Additionally, several beta designs, most notably of Wooper and Celebi, were found, along with a cut Girafarig pre-evolution and several crudely-drawn placeholder sprites.
- A beta build of Pokémon Diamond and Pearl got leaked, revealing cut designs, features, and music that was once tightly under wraps to the public.
- Pokémon Black and White ended up having almost the entirety of its Pokédex leaked by an unknown insider source. While the leaker didn't give names of the majority of the leaked creatures, they did leak their typings, as well as giving either vague descriptions of the Pokémon's appearance or even an illustration of what they looked like.
- Pokémon X and Y:
- The same leaker from the Black and White Pokédex leak struck again. While they didn't leak the majority of the Pokédex this time, they did disclose the advent of the new Fairy-type, the typings of the new Eeveelution Sylveon and the Legendaries Xerneas and Yveltal (Fairy for the former two and Dark/Flying for the latter), and the Retconning of previous Pokémon's typings to Fairy, with mentions going to the Clefairy and Togetic lines.
- Some game stores in Canada and Italy ended up breaking the street date for these games and sold them early. Naturally, many fans ended up snagging these games while they could and leaked just about the entirety of them online. Also naturally, many of these fans ended up getting takedowns from Nintendo/Game Freak, though by the time the companies striked, the leaks were already in wide circulation, thus rendering their efforts pretty much futile.
- Pokémon Omega Ruby and Alpha Sapphire had its demo datamined. It didn't reveal too much notable information... except for a new, monstrous form of the Mythical Pokémon Hoopa. Aside from that, however, not much information about the game was prematurely leaked.
- Pokémon Sun and Moon:
- The game's existence was leaked after Game Freak ended up placing trademarks on the logos. Additionally, the Japanese names for the three Starter Pokémon, as well as the names of the cover Olympus Mons and Marshadow were revealed in the trademark leak. Notably, Marshadow wouldn't be officially revealed for about a year after the official trademarking.
- Many snippets of the game's trailers ended up getting leaked before their release, revealing Pokémon such as Tapu Koko, Alolan Raichu, and the remainder of the Grubbin line. These leaks caused the Japanese versions of said trailers to be released online ahead of their scheduled times.
- The designs for the evolutions of the three Starter Pokémon were found in some leaked concept art◊. While initially met with skepticism, the reveal of Mallow, the girl shown in Incineroar's art, gave more credence to the leaks before they were finally verified via the game's demo getting datamined.
- As mentioned above, the game's demo ended up getting datamined. Inside the demo were images of all of the Pokémon in the Alolan Pokédex, including the aforementioned starter evolutions and several other unreleased creatures.
- Like X and Y before it, some stores ended up breaking the release date for Sun and Moon, allowing a handful of fans to grab the game early and leak its content. However, advancements in the 3DS hacking scene caused the ROM to get leaked online, leading to many more fans playing the game before release. Obviously, Nintendo did not take kindly to the ROM leak, and ended up console banning people who went online with illegal copies of the game. Despite this, the original leaker got off scot-free.
- Pokémon Ultra Sun and Moon found its way into circulation a little over a week before its official release date, resulting in the game getting datamined and leaked to the public.
- Pokémon Let's Go, Pikachu! and Let's Go, Eevee!: An anonymous 4chan poster leaked the details of the game, such as the Pokémon GO mechanics and a return to Kanto, through a text post. However, due to the leak being on April Fools' Day, many fans dismissed it as a joke before it was officially revealed. An image of the protagonist on Lapras was also leaked months before reveal.
Generation VIII
- Pokémon Sword and Shield:
- The game had a bunch of fake leaks going around, as usual. But one particular leak, dubbed the Affleck leak, released on 4chan on May 23rd, 2019, gave accurate descriptions of a lot of things that were indeed in the game, including both things that were later revealed in pre-release trailers (Dynamax and Gigantamax, characters such as Hop, Leon, Sonia, Bede, Marnie, Milo, Nessa, Oleana and Chairman Rose, Team Yell, the Wild Area, the camping mechanic, the Gigantamax forms of Meowth and Pikachu and Pokémon such as Zacian, Zamazenta, Wooloo, Yamper, Sirfetch'd and Cramorant) and stuff that wasn't unveiled officially until the game's release (the identities of the Fairy and Fire Gym Leaders, Galarian Meowth, Gigantamax Lapras, the starters evolutions, Skwovet, Greedent and Eternatus).
- Over the weekend of November 1st-3rd, just under two weeks before the game's release, screenshots both from the game and the strategy guide began flooding the internet, revealing basically the game's entire roster of Pokémon (which was a lot, considering that far fewer Pokémon had been officially revealed by that point as opposed to the run-up to previous game releases). The scale of these leaks as well as the increased scrutiny towards Sword and Shield that followed caused Nintendo to launch a full-blown investigation into the leaks, eventually tracing them to an employee for the Portuguese Nintendo fansite FNintendo, who had leaked the content from their review copy of the game. As a result, Nintendo permanently cut ties with the website, and the leaker was fired from their job.
- Less than a week before the release date, a store in Mexico broke the street date, resulting of videos of playthroughs of the game popping up.
- When Isle of Armor, the games' first DLC (and the first DLC in the history of mainline Pokémon games) was released, the dataminers set to work, and found that an enormous amount of data from the second DLC, Crown Tundra, was included. Among other things, this spoiled the map, chapter titles, and the existence of two additional Pokémon, much later revealed to be Glastrier and Spectrier.
- The existence and a few details of both Pokémon Brilliant Diamond and Shining Pearl and Pokémon Legends: Arceus was leaked by multiple sources prior to their reveal in the 2021 Pokémon Direct. In the latter's case, early screenshots were also leaked.
- The Diamond and Pearl remakes, Brilliant Diamond & Shining Pearl, were leaked by a YouTuber well before the game was actually released. Nintendo obviously did not handle it well, to the point of even bricking his Nintendo Switch.
- Ten days before the game's official launch, multiple copies of Pokémon Legends: Arceus surfaced on auction sites, and its files were swiftly dumped.
Generation IX
- Pokémon Scarlet and Violet:
- About four months before the games' release, a slew of previously-unknown information was leaked and spread online, including the fact that Wooper would get a regional form, some fuzzy pictures of Penny, all but one of the Gym Leaders, and the existence of Farigiraf.
- On November 4th, 2022, Pokémon GO data miners leaked the full form of Gimmighoul.
- Just under two weeks before the game's release, some physical copies broke street date and subsequently had their ROMs made available online, resulting in the entire Pokédex being revealed.
- On February 27th, 2023, the game was updated with the Tera raid release of Walking Wake and Iron Leaves. Within 24 hours dataminers found the entire roster of previous-generation Pokémon who would be returning in the upcoming DLC, which had only just been announced, were at least six months away and didn't even have definite release dates, had been added in to the game files.
- Shortly after the Indigo Disk was released the Mochi Mayhem Epilogue, the finale of The Hidden Treasure of Area Zero DLC, was found by dataminers before its official announcement on December 20th, 2023.
