To find Lugia go to the bottom right Whirl Island in Jhoto. Enter the cave. Jump over the wall at the top. Follow the path until you get to water surf until you get to the waterfall. Go down the waterfall. Go to the land on the left and go through the door. Go through another door and you will find Lugia in the water. WARNING there is only one Lugia! I caught Lugia with a masterball. After you have caught Lugia go back out to where the waterfall is and surf down and then to the right and you will find land go up the ladder and follow the path and you should find the exit to the cave.