you can only get it fire red and leaf green. so, no.
No you cannot catch Larvitar in Pokémon Emerald.
look on pokemon.marriland.com
Larvitar cannot be obtained unless you trade it from leafgreen or firered.
Egg.
Trade from Firered or Leafgreen.
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you can get the national dex from prof. birch after deafting the the elite four. then you can trade larvitar from leafgreen or firered. you can find larvitar in the seventh island in leafgreen/firered
You can catch a larvitar in emerald in any river as long as you choose the right bait and are full of patience. They are very tricky to work with so you must be keen and alert
Trading is required since it's not obtainable in the game.
Nowhere, because you can't find one in Emerald. You'll have to trade one from FireRed/LeafGreen.
the way is only to get it off fire red or leaf green. so, no.
answer: cannot be found, only in fire red and leaf green.