Pokémon's creatures come in all shapes and sizes, but some of the most interesting entries are the oldest Pokémon in lore. Discounting the legendary Pokémon that are commonly known by players and the Fossil Pokemon due to their deliberate origins as the Pokémon equivalent to dinosaurs, there are several regularly-encounterable entities that have different origins or diverse lore that shapes the world's history. The origins of these Pokémon date back millions of years, making them some of the oldest creatures in the games' universe.
The Pokémon here do not necessarily have specifically confirmed timelines of when they were prevalent, but the multiple Pokédex entries from the Pokémon games in the main series give some information regarding their history. It is through these entries that the species' general age can be confirmed. These Pokémon entries also tend to provide some information to show how they were incorporated into society or even came not to be.
One of the oldest Pokémon known to exist is Carbink, with their typical age allegedly reaching to the millions. The species was theoretically born from temperatures and collective underground pressures, and can even mutate into the Mythical Diancie. The species appears in Pokemon X & Y, with the latter's entry stating that the creatures tend to sleep for up to a million years after birth. While it can be hard to estimate how some entities in the Pokémon universe come to exist, Carbinks are essentially floating jewels and rock formations. With techniques from the modern world available, it makes sense that their age could be confirmed through technology available from researchers and scientists, which puts this fuzzy Fairy-Type as one of the oldest in the series.
Oldest Non-Legendary Pokémon - Relicanth
Relicanth is quite literally known as the Ancient Pokémon. It is based on the real-life coelacanth, described as being a living old Pokémon fossil due to being completely unchanged from its first discovery. In the Pokémon world, it takes on the form of an old, fossil-like fish that is renowned for its similar lack of change in over one hundred million years. These Pokédex entries confirm the age of the species, starting from its debut in Pokemon Ruby & Sapphire to present-day Sword & Shield. The in-game lore even nicknames them as living fossils much like their living counterparts, making it an assurance that they are one of the oldest species in the entirety of the universe.
Claydol & Baltoy Are Extremely Old Pokémon
Claydol and its baby form, Baltoy, debuted in Pokémon Ruby & Sapphire. This also marks it as the first man-made Pokémon species to date, due to the origins that their lore provides them. These Pokemon are, as the former's name suggests, sentient clay dolls that are powered by a mysterious ray, presumed to be psychic power. In Baltoy's original Pokédex entry from Ruby, the entry states that there are primitive pictures in wall paintings depicting the Psychic-Type living with ancient human civilizations.
The Claydol Pokédex entries further elaborate on their true origins by giving a definitive year range on when these creatures were first recorded. Their Pokémon Sapphire entry marks them at 20,000 years in the past, putting their age well above a lot of the other common species seen around it. In FireRed, it is even stated that the Claydol species was born from clay dolls made by the hands of the humans living in that era.
Oldest Non-Legendary Pokémon Ever - Mamoswine
The final evolution of the Swinub line that debuted in Pokémon Diamond, Mamoswine can also be found in Legends: Arceus. Based on a woolly mammoth, this behemoth of an Ice-Type was not given an exact context of age until Pokémon Platinum. In the entry, it is described to have been physically dug up from a frozen state dating back to 10,000 years ago. This only impressed those discovering the creature further when it abruptly woke up from its hibernation and was fully alive. While not as old as other entries on this list, that still marks it as being one of the oldest non-legendaries that are recognized in the universe.
Oldest Pokémon - Unown's Age Is Impossible To Truly Determine
Unown are a curious example, and attempting to pin down their sheer age is hard. The entire species is made up of forms of the creatures resembling ancient letters, exclamation points, and question marks. Pokémon Legends: Arceus has Unown sprinkled throughout the game, and it is depicted that these creatures were already around before the protagonist discovers their existence. The Pokédex does not give an exact date, but there is a large debate that questions if they came before or after the very first written language. This thus places them at a time before Hisui's settling. When putting this together, and with a quote from the character Cogita in Legends: Arceus that the earliest human settlement existed around a millennia before Hisui's creation, this puts them at least a millennia back and, as a result, makes them one of the oldest species.
Oldest Pokémon - Timburr Taught Humans How To Make Concrete
A more humanoid take on older species is the Timburr line of Pokémon. This Pokemon is another species that worked alongside humans, much like how many other Pokémon on this list interacted with the ancient civilizations in some way or shape. In present day, it can even be found in Pokémon Sword & Shield. In its Pokémon Black 'dex entry when it has fully evolved into a Conkeldurr, it is described to have taught humans how to utilize and create concrete over 2,000 years ago. This puts it below Mamoswine's 10,000 year age range, but still manages to make the Fighting-Types much older than a variety of the species now seen in modern times, beginning in Pokémon Red and Blue.
Most of these old-world species in the Pokémon universe can be found during times known as the Human Activity Age (in the case of Mamoswine and Claydol), or were otherwise grouped and considered to be the first normal Pokémon. The above Pokémon shows not only the age of the creatures, but also shows how old humanity was to be able to interact with these species. The older Pokémon, whether they survived extinction to the present day or remain only in the past like Hisui, help players paint how the olden times were to a smaller degree, including the usage of cave paintings and the hunting of Mamoswine by hunters.