The Inner Ocean is located in between the Isle of Berk and the Meathead Islands. Berk lies on the west of the Inner Ocean, while the Meathead Islands lie east of it. South of the Inner Ocean lies the Little Isles.
The Inner Ocean is first seen on the map at the beginning of this book. The sea itself does not figure into the storyline, but some of its coast areas - Long Beach and Death's Head Headland - do appear in it.