You need to get the Eon Ticket.
You can get it by mixing records with ruby or Sapphire that has an Eon ticket.
you cant. You can only catch it in Pokemon emerald, but, you cant catch latias in emerald.
Anywhere.
No, you can only get Latias in Sapphire and Emerald and Latios in Ruby and Emerald.
Southern island. Get one from emerald or ruby.
a master ball!!!
randoom agen!
One way is to trade with another emerald or you could trade your latias (or latios) to another emerald then restart the game and choose the opsite then catch it and trade back.
When you defeat the Elite Four go search for it and it will be on your Pokedex. It will tell you where is it. But if you move to that place it will be on a new area. If you want to get Latias then you will have to get a ticket to Southern Island in Wireless Adapter. It will be at lv.40 when you geta Latios and Latias will be at Lv.50 when you catch it at Southern Island.
you go fly in the air and catch him with a net
There is an event where you can catch Deoxys, Lugia, Ho-Oh, Mew and either Latias or Latios depending on what color you chose. I believe you can only do this after you beat the Elite Four. Mew is at Faraway Island. Latias or Latios is at the Southern Island.( depending on what color you chose after beating the Elite Four) Deoxys is at Birth Island. And Lugia and Ho-Oh are at Navel Rock. Good luck.
Is to never give up on finding and capturing Latias or if your friend has Latias from his Pokemon games, he can trade it with you if he/she wants.
You can fight in the battle tower, catch the three regis, search for latios/latias, or in emerald you can catch groudon and kyogre