Pokemon
¤ Red and Blue
¤ Red and Green (Japanese)
¤ Blue Version (Japanese)
¤ Yellow Version
¤ Gold and Silver
¤ Crystal Version
¤ Ruby and Sapphire
¤ Emerald Version
¤ FireRed & LeafGreen
¤ Diamond and Pearl
¤ Platinum Version

Universal Information
¤ What is this section?
¤ Breeding Pokemon
¤ Elemental Types
¤ Pokerus Infection
¤ Shiny Pokemon

Affiliates
¤ Amity Square
¤ Dark Eon Hideout
¤ Eevee's Headquarters
¤ Jenviousity
¤ Lugia's Island
¤ Perfect Absolution
¤ Pokemon Inferno
¤ Pokeshore
¤ PokeTech
¤ Pokeuniverse
¤ Pokemon Valley
¤ Sapphire Milotic
¤ The Spriting Shack

There isn't much on Naval Rock. Enter the cave and proceed north and you'll come to a ladder.

The next room is small with another ladder going down. Follow the next path and don't take any paths that branch off from here. They lead to nothing. You'll come to a fork. The left takes you to Ho-oh, and the right takes you to Lugia. Both paths are very long and the room repeats for 3-7 floors. @.@ At the end you'll find Lugia or Ho-oh. When you do reach either one, save! You don't want to kill it and have to come all this way again. Both birds are at Level 70.

As with previous encounters of either bird, it will be difficult to catch them because they know the move Recover and can restore large amounts of HP. Putting them to sleep then attacking may help you knock down their health without the threat of a sudden heal.

A Pokemon that knows Surf/Icebeam/Thunderbolt should be brought along, but it shouldn't be too strong as one move could kill them in either turn. Use the move until they have orange/red health. If you manage to freeze them, good. If that didn't happen, switch to a Pokemon that knows Sing/Sleep Powder and use it. Proceed to hurl Ultra Balls until they are caught. You may have to repeat it if it uses Recover. Keep this up and it'll soon be yours.

Backtrack and take the opposite way when you want to find the other bird. Just repeat the battle step.