Golduck have webbed hands and feet, ending in broad flippers, which they use to swim in rivers and lakes, much in the way as a duck would move. Their blue bodies are especially adapted to have a great hydrodynamic shape, and they have long tails with which they use to steer. Due to their bluish color and webbed hands and feet, Golduck are sometimes mistaken for the Japanese monster and physical inspiration for Golduck, the Kappa. Golduck also have red irises, a small, red sphere on their forehead, and four spikes on their head. Though Golduck have no wings, only webbed hands and feet, it is still deemed as a duck instead of a platypus
Golduck are fast swimmers, outswimming even the most athletic of humans because of their frog-like webbed hands and feet. The gem on their foreheads glows when they use their psychic powers, and occasionally when they swim at full speed, suggesting that they sometimes use those powers to swim. As shown in the Pokémon Adventures manga, after evolving from Psyduck, Golduck have greater control of their powers. They have the ability to read minds or even give knowledge to their trainers and fellow Pokémon through telepathy. It has been noted that Golduck will often join swimmers when training. They are sometimes found rescuing people lost at sea from danger, their heads shimmering from the telekinetic powers that allow them do so. The headaches that ridiculed its Basic evolution form, Psyduck, don’t trouble Golduck, allowing them to have full use of their formidable mental powers.