In the original Ruby, Sapphire, and Emerald games, Dive Balls were 3.5x effective on underwater Pokémon (i.e., Pokémon you encounter while diving).
In every game since then, from FireRed to X and Y, Dive Balls are 3.5x effective on water-dwelling Pokémon (i.e., Pokémon encountered while surfing, or from fishing).
Since Omega Ruby and Alpha Sapphire are both recent games, and games with underwater Pokémon, when would Dive Balls be extra effective? Underwater, surfing/fishing, or both?
Neither Serebii nor Bulbapedia appear to provide an explicit answer here.
Best Answer
According to Bulbapedia:
As you can see here, in ORAS Dive Balls work the same as in third generation.
The enhanced catch rate is not specified for ORAS, but is reasonable to think that it hasn't changed.