To get to Seafoam Islands, surf down from Fuchsia City, past the trainers to the very bottom, and go left. You will be able to enter through the entrance. You can also surf right from Cinnabar Island, past the many trainers. However, this time, you will enter through the exit. You can catch a lot of water pokemon here, and the legendary ice bird, Articuno. The water pokemon here are: Horsea, Seadra, Seel, Dewgong, Shellder, Slowpoke, Krabby (blue), Kingler (blue), Psyduck, Golduck, Goldeen, and Staryu.












You can gain a lot of levels here for your electric and grass typed pokemon. Now for Articuno: There are a couple of floors with ladders and holes. There are boulders beside these holes. Use your strength pokemon to push in these boulders. When they are pushed in, they will change the current of the river down below. Remember to heal your pokemon first. Go out of the Seafoam Islands and come back in. I need you to be at the very beginning. Follow the maps below to find out the way. The descriptions are below each map.
Articuno, like Zapdos, is level 50. It is a ice and flying typed pokemon. It has Ice Beam and some other moves. Use a fire or electric pokemon to weaken it first. Use Leech Seed too. Then, use Hypnosis to make it go to sleep when it is running very low on HP. Thor wsome Ultra Balls to capture it. If you have Master ball, you could use it but you should save that for Mewtwo. You could do the Master Ball Cheat but you need to have the Master ball with you too.
Now you can stay and gain more levels or you could leave. If you are getting impatient, just use an Escape Rope to go back to the Pokecenter.