This guide's length necessitates two parts. This section introduces Shiny hunting and several methods of increasing odds. To jump to the second section, which contains the other Shiny hunting methods, click here.
Ever since their introduction in Generation II, Shiny Pokémon have been some of the most treasured trophies obtainable. They’re incredibly rare, however: the odds are so low, you can play for hundreds of hours without finding any. To make the search less tedious, each game offers methods to increase the chances of finding a Shiny (dubbed "Shiny hunting"). All make it easier to find these elusive Pokémon, but the rates vary by method and game.
Note that from Generations II to V, the base Shiny odds were 1/8192, or 0.01% for any given encounter. With Generation VI's release, base Shiny odds were doubled to 1/4096, or 0.02%.
Wild encounters
The most obvious — and most difficult — way to find a Shiny is through random encounters. As mentioned, the odds of a Shiny Pokémon appearing in the wild are either 1/8192 or 1/4096, depending on the game. However, there are modifiers to make it easier to find Shinies in the wild, which are essential for anyone wishing to Shiny hunt efficiently.
Note that some Pokémon are Shiny locked, meaning they can never be Shiny. This mostly pertains to story encounters like Zekrom and Reshiram in Unova and the Galarian starters at the start of Sword and Shield.
Breeding
Breeding two compatible parents will produce an Egg that has a chance of being Shiny. In most cases, this has the base odds of the generation you’re playing. There are ways to boost your chances, though:
Introduced in Generation IV, the Masuda Method significantly increases the chance of breeding a Shiny when specific conditions are met. Two compatible parents of different nationalities must be placed in the Daycare (e.g. an English Pikachu and a Japanese Ditto). The resulting offspring will have a higher chance of being Shiny, with odds of 1/1638 in Generation IV, 1/1365 in Generation V, and 1/683 from Generation VI onwards. The Masuda Method can be stacked with the Shiny Charm starting in Generation V in order to further increase the odds.
In Generation II only, shininess is determined through IVs. If one parent has the "Shiny gene" — a certain combination of IVs — and is the opposite gender of the offspring, the latter has as high as a 1/64 chance of being Shiny. This method only works in Generation II and can get fairly complex; Bluwiikoon's guide is an excellent resource for further reading.
The Odd Egg in Crystal can hatch into one of seven Baby Pokémon: Pichu, Cleffa, Igglybuff, Tyrogue, Smoochum, Elekid, or Magby. In international releases, the Egg has a 14% chance of containing a Shiny Pokémon. In Japanese editions, the Pokémon that hatches has a 50% chance of being Shiny, though obtaining a Japanese Odd Egg requires a now-defunct event. Internationally, the Egg is given by the old man at the Daycare Center on Route 34.
There are no Shiny Pokemon in Generation I, but transferring them to Generation II gives them a chance. Since shininess is determined by IVs, it’s possible to transfer a Generation I Pokemon to Generation II via the Time Capsule and find that it’s Shiny. Only fishing encounters, static encounters, gift Pokémon, and in-game trades have a chance of being Shiny when transferred.
Guaranteed shinies
There are a few Shiny Pokémon obtainable through a game's natural progression. There aren’t many of them, and even fewer are easy to find.
In all Johto games (GSC, HGSS), a Shiny Gyarados waits at the Lake of Rage. Battling it is required to progress, and it won’t respawn if you knock it out.
In Black 2 and White 2, if you see every non-Mythical Pokémon in the Unova Pokedex, you will be granted access to the Nature Preserve. In the middle of this area resides a Shiny Haxorus, available for you to battle and catch whenever you choose.
Black and White 2 also hold two other guaranteed Shinies: Gible and Dratini. Each is a reward for defeating Benga in your game's postgame battle facility, with Gible in Black 2 and Dratini in White 2.
In Legends: Arceus, there’s a research quest available for a Shiny Ponyta. It can be found very early in the game and is consequently one of the easiest Shiny Pokémon in the series to obtain.
Scarlet and Violet's The Teal Mask DLC allows players to receive a Shiny Munchlax after clearing Ogre Oustin' on Hard difficulty for the first time. Additionally, in Scarlet and Violet's The Indigo Disk DLC, Cyrano trades the player a Shiny Blitzle after being invited to the League Club Room.
Select event distributions will yield guaranteed Shinies. Occasionally, Mystery Gifts have been (and will continue to be) distributed to players, rewarding them with Shiny Pokémon. Pokemon HOME's Shiny Zeraora is one of the more notable examples of such an event.
Poké Radar
The Poké Radar appears in Diamond, Pearl, Platinum, X, Y, Brilliant Diamond, and Shining Pearl. It's obtainable after receiving the National Dex and significantly boosts Shiny odds. Activating the Radar in a patch of tall grass will cause other patches to shake. Capturing or knocking out the Pokémon in that grass will start a chain, which can be continued by repeatedly capturing or knocking out Pokémon of that same species. At the maximum chain of 40, Shiny odds in DPPt and XY are around 1/200 (0.5%) per patch. The BDSP odds are higher -- a chain of 40 yields 1/99 odds (about 1%). For more information on BDSP's Poké Radar mechanics, refer to Serebii's guide.
Cute Charm Glitch
The Cute Charm Glitch offers some of the highest Shiny odds in the game, with a whopping 21% chance per encounter when executed perfectly. However, it’s extremely difficult to set up, as the glitch requires manipulating personality values and Trainer IDs. It’s best to check a professional guide like Smogon’s for a more thorough grasp on how to use the glitch. There are other glitches you can use to manipulate Shiny rates; again, the Smogon article provides an overview of these.
Shiny Charm
The Shiny Charm, introduced in Black 2 and White 2, is one of the most useful items for Shiny hunting. It significantly boosts Shiny odds and stacks with other hunting techniques. In its debut games, the odds are roughly triple that of the standard odds, with a 1/2731 (0.04%) chance of finding a Shiny on any given encounter. In later generations, due to the increased base Shiny rate, the Shiny Charm now raises odds to about 1/1365 (0.07%). When combined with other methods like the Masuda Method and Dynamax Adventures, the odds are even higher. However, in Scarlet and Violet, wild Tera Pokémon and Pokémon found in Tera Raids are not affected by the Shiny Charm.
Note in Brilliant Diamond and Shining Pearl, the Shiny Charm only works when breeding.
Friend Safari
The Friend Safari is a postgame location in X and Y that contains Pokémon typically unobtainable in Kalos. It also offers increased Shiny odds, at a 5/4096 (0.12%) chance. The Shiny Charm increases odds for this method to 7/4096 (0.17%).
Consecutive Fishing
Exclusive to Generation VI, consecutive fishing (commonly called chain fishing) is a mechanic that offers significantly higher Shiny odds. If you don’t move from your fishing location, always come up with a bite, and time your reels correctly, you can start a streak that progressively ups your Shiny chances. The odds cap at around 1/96 (about 1%) after twenty consecutive battles — some of the best odds in the series. Thonky’s guide is a great place to learn more about chain fishing and optimal strategies.
DexNav
In Omega Ruby and Alpha Sapphire, the DexNav yields higher Shiny odds. As your search level and chain increase, the chance of encountering a Shiny Pokémon improves. Shiny chances increase with search level independently from your chain, but your chain also increases your odds of finding a Shiny at every 5th, 50th, and 100th encounter. This is displayed in this table from Bulbapedia.