>>37955760Deoxys-Speed Form is a contender considering its ingame stats put it at a maximum speed of 504, the fastest of any pokemon without boosts or items.
For Dex entries, Dragonite is capable of long-distance travel at 1,556 mph, and Latios can travel "faster than a jet", but that doesn't really give any details. Golduck's entry states that "Golduck is the fastest swimmer among all Pokémon", so there's no debate there.
Land speed is less certain, but Zeroara is said to be able to move "as fast as lightning", which a cursory google search says is 62186828.91911 miles per hour. Idk if that's right though.
