These waters comprise the Aerdi and Oljatt Seas, the Tilva Strait, and the Spindrift Sound. The Scarlet Brotherhood controls much of these seas, contesting northern areas with the Sea Barons and in a few incursions from Ice Barbarians. Eastward along the north coast of Hepmonaland, a handful of pirates - some reputed to be sea-going hobgoblins - occasionally foray westward.
The warm, blue-green depths of the Oljatt Sea are particularly beautiful, and also particularly dangerous, with many sea serpents and octopi of great size, capable of dragging down smaller vessels. Ships were often chained together in great convoys to prevent this fate, and seamen typically carry pikes to fend off such monsters. The Tilva Straits and Aerdi Sea are known to be shark-infested.
The Solnor Ocean and the vast Grendep Bay are disputed among the Sea Barons and Ice Barbarians, the latter holding greater sway the farther north one goes. Great whales throng the Solnor, which is said to stretch for a thousand leagues eastward. In summer, Ice Barbarian longships carry great harpoons, although their whaling is opportunistic rather than well-organized. The Ice Barbarians do not travel much in Grendep Bay in the fall, for monsters greater in size even than whales can be seen at sport there.
Marner is a vital port along the coastline - the major port for Ratik from which a little trade still manages to filter down to eastern Aerdy states, although this is very hazardous.
Relmor Bay, Woolly Bay, and the Sea of Gearnat are well mapped, with excellent navigator's charts readily available. The humanoids of the Pomarj do not appear to be setting sail just yet, so traders headed from Greyhawk to Nyrond can still sail in relative safety, although the route through the Nyr Dyv and via Urnst is increasingly preferred. To the east, Nyrondese naval vessels dominate Relmor Bay still, only occasionally skirmishing with bandits and brigands operating out of the old South Province. A handful of Irongate vessels still risk the journey to Nyrond also.
Woolly Bay is known to contain groups of scrags (marine trolls) which may have coastal lairs in the Pomarj. Vessels traveling this bay often have many readied spears covered in thick balls of wool and pitch, ready to ignite and use against these creatures.
The vessels of the Scarlet Brotherhood hold complete dominion here - in the Densac Gulf, Azure Sea, and Jerlea Bay. While peace allows traders to sail these waters from the north, few take the chance. The Azure Sea has always had a plentiful share of sea monsters, and most traders used to stick to the coasts of the Iron League states, but monsters seem to be more common there now (unless the ships are those of the Brotherhood, strangely enough). Kraken and coastal sea lions are among the hazards of the Azure and Jerlea Bay, and rumors of morkoths laired around the Olman Islands are a deterrent to travel in the Densac Gulf. The Gulf itself is said to open into a vast ocean stretching well into Lower Oerik, but its waters are unmapped beyond northern Amedio.
The Scarlet Brotherhood has by no means subjugated all of Amedio. Along its coastline and small offshore islands, pirated prove as irksome a threat to Brotherhood ships as they previously did to those of other nations. Some of these pirates are said to be assisted by weather-controlling magic, and to use arrows coated in paralyzing alkaloid poisons from the jungles.
The western half of the Azure Sea is also known to be infested with great swathes of seaweeds that slow ships and render the air foul and noxious, in addition to concealing monsters such as merrow and scrags.
The deep blue waters of this great sea stretch far to the west beyond the reach of the mapmaker. Where the warm currents that enrich the coastlands of Zeif and Ekbir flow northward, the collision with colder waters generates great fogs and icebergs that have been seen as far south as Ekbir during the spring, suggesting the presence of great ice floes in uncharted northern areas. Among the unusual seaman's tales of monsters and terrors of the deep, stories of aquatic deadly puddings that cling to the hulls of ships and rot them away from underneath while slowing passage are not to be taken lightly.
The Icy Sea is frozen over in great areas except during high summer, during which time Ice Barbarians sometimes hunt here for walrus ivory, killer whales, and seal furs. Even at such times, the sea is dangerous due to thick fogs and floes of pack ice. White Fanged Bay is aptly named after a ragged coastline that resembles the teeth of a great predator. The seals and walruses here are hunted by the men of Stonefist.
This is the third greatest body of fresh water in the Flanaess. It is almost exclusively the preserve of Perrenlandm whose men fish its rich waters in all seasons save winter. Perch, tench, roach, pike, and freshwater trout all teem within the waters. The lake is also said to be home to a family of mist dragons on a perpetually mist-shrouded small central island within the lake. Perrenlanders hunt the waterfowl along the shoreline, as do the Wolf Nomads from time to time.
This great lake, also known as the Lake of Unknown Depths, is a strategic body of water. Across it, much trade is plied between Greyhawk, Dyvers, Furyondy, Urnst, and the lands beyond as fas as Perrenland and the Theocracy. As the map shows, many major ports and navigable inlets and outlets throng the waters of the Nyr Dyv. The navies of Furyondy and Urnst still dominate this great lake, protecting the shipping that travels it; Iuz has not yet sought to extend any naval strength to the Nyr Dyv.
One of the most unusual features of the Nyr Dyv is its people. These folk make their homes on great barges anchored along the shores. They conduct much of the day-to-day conveyance of trade along them. These are the Rhennee, gypsy waterfolk who are mostly thieves and occasionally pirates.
Each Rhennee barge is crewed by a "lord" who shares his cabin with his family, and "cousins" (who may or may not be related by blood) who find living space on or below deck. A typical barge contains some 15-20 souls. The Rhennee have both a special cant of their own and a subtle communication systems using flags and lanters.
The Nyr Dyv is also home to many monsters. Freshwater serpents and octopi have often been reported, as have freshwater aquatic umber hulks and worse. A notable feature of a more pleasant aspect is a large community of selkie off the coast of Oldred, who do their best to warn sailors of possible hazards of this type. The selkie are known to be unfriendly towards Rhennee.
Before the rise of Iuz, much trade plied this lake - to and from Dora Kaa and Crockport, and up and down the Veng from the Nyr Dyv. Only the latter (and that hazardous) survived Iuz's unification of his lands. Since the Wars, when Furyondian vesseld mostly had to flee down the Veng, Iuz controls these waters completely. Iuz is not much given to shipborne attacks, and is not renowned for his skill as a strategist in naval battles, so little traffic is to be found on this lake now.