The Great Southern Ocean is so named because originally, sailors believed it went on forever. It is techniaclly the second largest ocean after the Palhuric. It contains the southern Eastern Sea suboceanic area. It is often abbreviated GSO.

Seas of the GSO:
Rolling Sea*
Eastern Sea*
Maljun Sea
Sea of Sapphires
Har'Uram Sea
Anjuri Sea
Basuri Straits
Ochre Sea
Wasp Straits

*Part of the southern Eastern Sea area.

Nations of the GSO**: "contains" indicates the sea is within the nation, but the nation is not limited to the sea.
Eshaugar - Si-te-cah
Bikkomeer - Har'Uram Sea; Bendus
Durnok - Handur
Prithiri - Sea of Sapphires
Amoloth - contains Maljun Sea
Monbaru - contains Anjuri Sea, Ochre Sea, Basuri Straits

**Does not include southern Eastern Sea nations.