Bodies of water of the North Sea

The Danish straits are the straits connecting the Baltic Sea to the North Sea through the Kattegat and Skagerrak. Historically, the Danish straits were internal waterways of Denmark; however, following territorial losses, Øresund and Fehmarn Belt are now shared with Sweden and Germany, while the Great Belt and the Little Belt have remained Danish territorial waters. The Copenhagen Convention of 1857 made all the Danish straits open to commercial shipping. The straits have generally been regarded as an international waterway.

The Firth of Forth (Scottish Gaelic: Linne Foirthe) is the estuary, or firth, of several Scottish rivers including the River Forth. It meets the North Sea with Fife to its north and Lothian to its south.

The Weser () is a river of Lower Saxony in north-west Germany. It begins at Hannoversch Münden through the confluence of the Werra and Fulda. It passes through the Hanseatic city of Bremen. Its mouth is 50 km (31 mi) further north against the ports of Bremerhaven and Nordenham. The latter is on the Butjadingen Peninsula. It then merges into the North Sea via two highly saline, estuarine mouths.

The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busiest shipping area in the world.

Southern Bight, also known as the Flanders Bight, and (in Dutch) the Hoofden, is the southern bight of the North Sea bounded by the coasts of the Netherlands, Belgium, France and Great Britain. The Southern Bight is south west of the German Bight and the Wadden Sea. The Southern Bight is roughly delimited in the north by a roughly straight line between The Wash and the West Frisian Islands going south of the Dogger Bank, a large shallow part in the North Sea, and the Outer Silver Pit, a deep water channel south of the Dogger Bank. It corresponds to sea area Thames and the northern part of sea area Dover.

The Wadden Sea (Dutch: Waddenzee ; German: Wattenmeer ; Low German: Wattensee or Waddenzee; Danish: Vadehavet; West Frisian: Waadsee; North Frisian: di Heef) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of low-lying Frisian Islands, forming a shallow body of water with tidal flats and wetlands. It has a high biological diversity and is an important area for both breeding and migrating birds. In 2009, the Dutch and German parts of the Wadden Sea were inscribed on UNESCO's World Heritage List and the Danish part was added in June 2014.

The Ythan Estuary is the tidal component of the Ythan River, emptying into the North Sea 19 kilometres (12 mi) north of Aberdeen, Scotland. The estuary’s tidal action extends a 7 kilometres (4.3 mi) inland and has characteristic widths of between 250 metres (820 ft) and 780 metres (2,560 ft). Besides the tidal channel there are interfaces to the upland dunes including mudflats, sand beaches and shingle flats. Reaches of salt marsh occur, but they are primarily near the Waterside Bridge (crossing of the A975 road) and the mouth of the Tarty Burn, a small tributary river. Based upon the habitat of the moorland bordering the east of the Ythan River near the mouth, this estuary is the most significant coastal moorland in the northern United Kingdom.

The Firth of Tay (Scottish Gaelic: Linne Tatha) is a firth on the east coast of Scotland, into which empties the River Tay (Scotland's largest river in terms of flow). The firth is surrounded by four council areas: Fife, Perth and Kinross, Dundee City, and Angus. Its maximum width (at Invergowrie) is 3 mi (4.8 km).