Same as Generation I, but the user cannot avoid Earthquake, Magnitude, or Fissure during the semi-invulnerable turn, and will receive double damage from Earthquake and Magnitude, unless the digging Pokémon would not receive damage from the moves normally (i.e. Flying-type Pokémon or those with the Ability Levitate).
^Refers to Dig. Source.
On the first turn, the user will dive down for one turn and become invulnerable to most attacks, with the exception of Surf and Whirlpool, which will do twice the damage to the submerged Pokémon.
^Refers to Dive. Source.