In OpenStreetMap the primary division of the earth surface into land and water is mapped through ways tagged with natural=coastline. For rendering a map however you usually need land or water polygons representing continents and islands in the former or oceans on the latter case.
Assembling these polygons from the coastline ways in OpenStreetMap is done with a specialized processing tool (OSMCoastline). Learn more about the coastline processing...
The results of this can be downloaded here.
Polygons for all land areas in the world, ie. continents and islands. Large polygons are split into smaller overlapping chunks that are easier and faster to work with.
Polygons for oceans and seas. These polygons are split into smaller overlapping chunks that are easier and faster to work with.
Linestrings for coastlines. Long linestrings are split into smaller chunks that are easier and faster to work with.
Coastlines and corresponding polygons generalized for rendering well readable maps at coarse scales.
Not what you're looking for? There are other OpenStreetMap data sources where you might find what you need. Or you can commission us to develop new data processings.