Most sea creatures remain under water. They get their oxygen from the water so they never need to go to the surface. Whales, seals, penguins and turtles are other sea animals that breathe air and must regularly come to the surface.
Seabirds fly over the water. They may dive, skim over the surface, hover, swim or float when fishing. A few birds like penguins have given up flying and mostly swim below the surface.