Whirlpool inflicts 1/16 of the target's maximum HP as damage for two to five turns upon use, in addition to the damage dealt when it is used. The text "<Pokémon> was trapped!" will appear. It also traps the target, preventing switching and escape. If a trapped Pokémon uses Rapid Spin, it will be freed.
Whirlpool has a power of 15 and an accuracy of 70.
Generations III and IV
Whirlpool can hit Pokémon during the semi-invulnerable turn of Dive, and if it does, it will have its power doubled.
If a wild Pokémon uses Whirlpool on the player's Pokémon, the player may escape if the affected Pokémon has Run Away or is holding a Smoke Ball. However, these do not allow the player to switch the Pokémon out. The text also changes to "<Pokémon> was trapped in the vortex!"
If the user of Whirlpool is holding a Grip Claw, the duration will always be 5 turns. Also, if an affected Pokémon is holding a Shed Shell, it can switch out.
Whirlpool's power and accuracy were increased to 35 and 85 respectively, and it now lasts for four to five turns. In addition, if the user of Whirlpool is holding a Binding Band, it inflicts 1/8 of the target's maximum HP instead of 1/16 when the target is trapped.
If Whirlpool hits Pokémon during the semi-invulnerable turn of Dive, now technically the damage will be doubled, resulting in virtually the same effect.
Generation VI onward
The end-of-turn damage of Whirlpool is increased from 1/16 to 1/8 of the target's maximum HP. If the user is holding a Binding Band, the end-of-turn damage will increase to 1/6 of the target's maximum HP. Ghost-type Pokémon cannot be trapped by Whirlpool.
Outside of battle
Whirlpool clears whirlpools in the field while surfing.
Piplup's body glows a blueish-white color and it raises its arms and beak to the air. It then opens its beak and a huge whirlpool comes out of it and forms above Piplup. Piplup then throws the whirlpool at the opponent. While in the water, Piplup's body glows multicolored, and a whirlpool forms around it, or Piplup spins its body and glowing white water appears and forms around Piplup's body. The water's glow fades and spins with Piplup, turning into a whirlpool. Piplup then spins into the opponent. Piplup can also change the size of the whirlpool by choice. When Piplup is near the water, after it forms the whirlpool, it throws it at the water in front of the opponent, creating a large water vortex that sucks the opponent up.
If a player teaches a Pokémon Whirlpool by HM in HeartGold and SoulSilver and trades it to Diamond, Pearl, or Platinum, the Pokémon can be freely imported to Black and White via the Poké Transfer, due to Whirlpool not being needed outside of battle in Diamond, Pearl, and Platinum. The same can be done with Defog by transferring a Pokémon that learned it by HM in Diamond, Pearl, or Platinum to HeartGold or SoulSilver.
This move was Poliwrath'sattack (as うずしお / Whirl Tide in Japanese and as Whirlpool in English) in the Base Set set of the TCG prior to being introduced in Generation II of the games.