According to Bulbapedia and Serebii, Fairy Lock prevents all Pokemon on the field from switching or fleeing.
I've been wondering in regards to the potential viability of this move, whether it also prevents the use of moves such as Volt Switch, U-turn, Roar or Teleport, which either switch out the user or the opponent.
For example, I know that Mean Look prevents Teleport, but it doesn't stop the switching moves or Roar.
So, does anyone know what will and wont work against Fairy Lock?
Best Answer
As long as the Pokémon that originally used the move remains in battle, then all Pokémon are prevented from switching out. As there are no exceptions noted, moves such as Roar won't affect the battle. It should be noted, however, that Ghost-type Pokémon are naturally immune to this move.
It can be seen in this video that Baiziken can't switch with Gengar due to the Fairy Lock, but when used against a Gengar the user is able to switch Pokémon.