From OpenStreetMap Wiki
|natural = reef|
|A feature (rock, sandbar, coral, etc) lying beneath the surface of the water|
|Used on these elements|
|Status: In use|
|Tools for this tag|
Ais a rock, sandbar, or other feature (such as coral, stromatolites...) lying beneath the surface of the water (80 meters or less beneath low water).
How to map
If known you can add the following tags:
This tag should not be used for:
- features that raise above the water - use natural=shoal, place=island or place=islet for that.
- for the lower part of beaches lying below the water level - these should be part of a natural=beach.
- tidal flats, i.e. flat areas exposed at low tide but water covered at high tide - use natural=wetland + wetland=tidalflat instead.
- natural=shoal for features that lie above the surface of the water
- natural=beach for beaches
- natural=wetland + wetland=tidalflat for tidal areas
- Overpass Query to display reefs on the map. Zoom to the area you need and press execute in the top left corner.
- subsea=* and sub_sea=*, alternative tagging