Blue Sea

The Blue Sea is the huge body of water that covers most of the the world of the series. It is where most of the plot takes place. It was first mentioned in Skypiea, as a separate portion from the White Sea of the skies, even though it first appeared in Chapter 1 and Episode 1.

The Blue Sea is divided into four oceans: the North Blue, the South Blue, the East Blue, and the West Blue. These division are made in part by the Red Line and the Grand Line.