Ok. Latias in Ruby, Latios in Sapphire, Lati@s in Emerald
1. Get all 8 gym badges and beat the elite four. Latias will NOT be available until this is done.
2. Once the credits have rolled and you're in your house in LittleRoot, go downstairs and watch the television when you get the chance. It will inform you of a red flying Pokemon wandering around Hoenn (Obviously, Latias).
3. Go back upstairs, and if you have stored your Masterball in the PC, withdraw it now. If not, be sure you have it. If you have not wasted it. Skip to step 6
4.If you have wasted your masterball on Kyogre or Rayquaza, I apologize. This is going to be a bit tougher for you. Get a Trapinch or a Wobbuffet at a high level, OR it'd be a lot better to get a high leveled Pokemon that knows Mean Look (maybe a Zubat or Golbat from Victory Road). Give the Pokemon that has Mean Look the Quick Claw and spend some money on a few Carbos for it to be sure it's a top speed. Put this Pokemon at the top of your party. (if you have wasted your masterball)
5. Buy tons of Ultra balls. (if you have wasted your Masterball)
6. Be sure you've got a Pokemon that knows Surf, and one that knows Fly.
7. Fly to Mauville. Go east and surf across the water on Route 118. Cross east through the grass and onto the route that the Berry Master's house is on, be sure that you are standing to the east of his house. Is it raining? If so, you're in luck. If it is not raining, skip to the end of the steps, to the SPECIAL step.
8. I'm sure you've realized that it doesn't normally rain here. Fly to Lilycove now.
9. Move east onto route 121, and surf south of Mt Pyre. Travel towards the Berry Master's house, but stay to the top of the route to get to the small pond near his house.
10. Surf in this small pond. Go through 6 or 7 Pokemon encounters, and run unless it's Latias. However it's a low chance that it will be right now.
11. After the 6 or 7 encounters, travel west again, past Berry Master's house, and onto the next route.
12 There should be a patch of grass right there when you first enter the route. Search in it. If you're lucky, you'll run into Latias within a few encounters. If you don't find her after 8 encounters, Fly back to Lilycove and repeat the process until you run into her. The location plus the rapid changing of your own location should bring her to you quickly.
13 When you run into Latias, throw the master ball immediately. Congratulations!
14. If you have wasted the ball, use Mean Look immediately. If you chose Trapinch or Wobuffet, whittle down her HP and throw tons of Ultra balls. If you kill her, reset. If she gets away, you can now track her with your pokedex, in the style you use to track the legendary dogs in G/S/C.
