Hey everyone,
For people who have beat the Elite 4, and the Champ... the easiest way to find them is this. First, be patient... you can have the pokemon (RED/LATIAS) (BLUE/LATIOS) caught within about 2 hours after you begin.
To make things easy... if you have a friend who has the pokemon, battle them and they will appear in your pokedex. Use this to track them down, and when you are on the same route as them... they will appear realy easily when you are on the same route as them.
If you can't get them in your pokedex... you can either just forget about it and wait until you meet them, or work your azz off. By this I mean do the following.
Fly to Mosdeep, and surf south through route 127, 128, 129. Playing Emerald, Ruby, and Sapphire many different times... I have noticed while watching my pokedex that this is were they spend most of their time. They go to the desert often, but everytime you fly the pokemon will fly to the other side of Hoenn. They never go west of the desert and Mauville, but do appear on the route between Mauville, and Slateport. Remember, everytime you fly... Latios/Latias move far from were the had been, and everytime you change routes by walking, surfing, or riding a bike the move one route over (on over left, right, down or up).
So... if I were you... don't use fly, except every so often... walk most of the places you go to... stay in a route... let a couple of pokemon attack you, and then leave the route... go back and forth and after some time you may be lucky enough to run to one of them.
It takes time, and will enjoy it more when you run into them without expecting it.
My record is catching Latios 3 hours after beating the Elite four, using the method above. Remember! Use a master ball if you still have it.
