The Sea is only traversable after gaining access to the Sea Cow in Castaway Cove. Almost all the continents and areas you will desire to visit touch the sea at some point, but only a few areas are accessible until they have later been visited following the story.
North of the Summerlands[]
Creatures[]
Northwest of the Summerlands[]
Creatures[]
East of the Summerlands[]
Creatures[]
South of the Summerlands[]
The sea to the south of the Summerlands is the first area of the sea visited upon gaining access to the Sea Cow.