Where do you get ice beam Pokemon Emerald?

Right, to find Ice Beam, surf a bit south and then go west. Carry on going west until you find a ship. Go in it and you will appear on the side. Go inside and follow the ladders and go in all the cabins and defeat all the trainers. Soon you will come into a place where there is the Captain in a White Suite. Near him is a Storage Key (you will need it so take it). Once you have done that go to the door which you couldn't open before and you will be able to open it. Inside you will find TM 13, Ice Beam.You can also buy it from the Game Corner in Mauville City for 4,000 coins, which is 40,000 gold if you buy all of it from the lady inside.) ===