The November 2022 release of Pokémon Scarlet and Pokémon Violet bolstered the franchise's existing roster of creatures to more than 1,000 unique species. Naturally, some of them are harder to catch than others. How difficult a given Pokémon is to catch is determined by a generally hidden stat fittingly called the "catch rate," a staple since the original games on the Nintendo Game Boy.
Legendary species are unsurprisingly the most difficult, but the Paldea region has introduced Legendaries and non-Legendaries alike with incredibly low catch rates. There's a level of variety among these Pokémon ranging from the flagship creatures to the new Paradox species like Roaring Moon.
10 Koraidon - 3
Both of the latest games in the mainline Pokémon series took a unique approach to the concept of the "flagship Legendary" creature. Instead of being a late-game encounter during the climax of the story, both Koraidon (Scarlet) and Miraidon (Violet) partner up with the protagonist as their trusty mount.
This time, it's a second Koraidon that can be caught as part of the post-game of Scarlet. Reaching the stage shouldn't pose too much of a hassle for players, but the dual Fighting/Dragon-Type incredibly low catch rate of 3 (amounting to 1.6%) can prove to be a grind.
9 Miraidon - 3
On the opposite end of the spectrum, Koraidon's counterpart Miraidon in Violet essentially provides the same level of challenge. Players will have been traveling with their companion Miraidon throughout the entire game, but they can find a second one in the mysterious Great Crater within Area Zero.
This dual Electric/Dragon-Type Pokémon also features a low catch rate of 3. Perhaps the unique challenge Miraidon poses is in being a competent Special Attacking Pokémon in its own right.
8 Wo-Chien - 6
In addition to the typical flagship Legendary creatures, Scarlet and Violet also introduced a few new species that appeared in the post-game content. Among them is the dual Dark/Grass-Type snail Wo-Chien who, like its counterparts, requires some thorough exploration of Paldea to find.
A shrine must be opened by collecting the eight Purple Ominous Stakes in the southern portion of the region. It isn't one of the Pokémon with the lowest catch rates in the games, or even the entire mainline series, but at a rating of 6, it's undoubtedly going to take some patience and work.
7 Chien-Pao - 6
Seemingly an aesthetic cross between a snow leopard and a prehistoric saber-toothed cat, Chien-Pao is another member of the Legendary Treasures of Ruin beasts. As expected, it has an identical way to discover as its counterparts.
At the top of a mountain that needs to be accessed via climbing or gliding, players can unlock its shrine by using all eight of the Yellow Ominous Stakes. It's a Dark/Ice-Type, and Chien-Pao is a fast Physical Attacker that will require trainers to plan accordingly beforehand before playing against the low odds to capture it.
6 Ting-Lu - 6
Resembling mammalians like moose or deer, Ting-Lu is another member of the Treasures of Ruin. This Pokémon carries the Dark/Ground dual typing and is found in a shrine tucked away in the north of the Paldea region. Players will need to collect all eight Green Ominous Stakes to unlock, as well as the gliding and swimming functions of Koraidon/Miraidon to efficiently get there.
With a catch rate of 6, players will need also need a team of Pokémon that can effectively check its immense Physical bulk and offense, with its HP and Defense being Ting-Lu's most impressive stats and the most likely assets to give trainers a hard time while trying to catch it.
5 Chi-Yu - 6
Rounding out the members of the Treasures of Ruin quartet of Legendary Pokémon is Chi-Yu. Keeping with the motif of its companions, it also has Dark as its primary Type, but with an interesting secondary typing of Fire considering it appears to be visually inspired by a goldfish.
And as with the other Treasures of Ruin, Chi-Yu is found in a shrine that's fittingly hidden behind the top of a waterfall in Area Two. Players will naturally need the eight Blue Ominous Stakes to unlock its shrine in addition to the climbing ability necessary to reach it. Chi-Yu leans heavily into its Special Attack and Defense on top of an impressive Speed stat.
4 Baxcalibur - 10
As is tradition, Scarlet and Violet introduced its resident "Psuedo-Legendary" Pokémon, as dubbed by the fan base. Baxcalibur is quickly becoming one of the best Pseudo-Legendary Pokémon thanks to its sheer offensive power in battle.
The dual Ice/Dragon-Type creature isn't normally found in the wild, at least not compared to its more common (but still rare) base from Frigibax. However, it can be found through Tera Raid Battles, making it an especially tough catch thanks to the combo of a 10-rated catch rate and bolstered stats in battle.
3 Roaring Moon - 10
Standing among the strongest Physical Attack-oriented Pokémon in Scarlet and Violet is the Paradox beast Roaring Moon. Exclusive to the former game, this dual Dragon/Dark-type species takes clear influence from the Hoenn-native dragon Salamence, but it features even more bolstered stats.
That level of power comes with an equally low catch rate of 10. Located in Area Zero of the Paldean region, Roaring Moon, as well as another Paradox counterpart, will prove to be among the most difficult Pokémon to catch.
2 Iron Valiant - 10
On the Violet side of the Paradox Pokémon available in Paldea, Iron Valiant will be another grind to capture. A dual Fairy/Fighting-Type, Iron Valiant is a futuristic species reminiscent of Sinnoh's Kirlia evolution Gallade. It's an incredibly competent mixed attacker thanks to its near-equal Physical and Special Attack stats.
Likewise, it also has a low catch rate of 10 and can only be found in the post-game Area Zero located in Paldea's Great Crater. Trainers will need to come prepared with a team that can outlast Iron Valiant's offenses, especially since it's found in levels ranging from 56-59.
1 Armarouge - 25
Another version-exclusive Pokémon (but not under the Paradox category) is Armarouge. The dual Fire/Psychic-Type knight species is the Scarlet-exclusive evolution of Charcadet when exposed to the Auspicious Armor item. As far as low catch rates go, Amrarouge's standing at 25 is one of the more merciful in the Generation IX games.
Even so, for not being a Legendary or Pseudo-Legendary Pokémon, its odds are still fairly tough to deal with. Armarouge isn't normally a "wild" Pokémon, but it can be found in high-level Terra Raid Battles.