U-turn deals damage and then switches the user out. The user will not be switched out if the user is the only Pokémon in the party that is able to battle, if the target's Ability is Wimp Out, or if using U-turn ends the battle. If U-turn faints a foe Trainer's Pokémon, the next Pokémon sent out by the user will not be counted for additional experience and if the user is battling an NPC, the player will still have the ability to switch Pokémon in between Pokémon that have fainted. If the next Pokémon sent out by the user is holding the Amulet Coin or Luck Incense, it will be counted for that even if it is immediately switched out in between fainted Pokémon.
If the foe Pokémon uses Pursuit on the same turn U-turn is used, Pursuit will deal normal damage if the foe is faster, or double damage if the foe is slower than the user.
In Pokémon Diamond and Pearl, if the Pokémon selected after the switch-out is holding a Choice item and also knows the move U-turn, they will be forced to use U-turn as their next attack despite not having made a move.