The harbour
The Index rates Otaru Ko a medium-sized coastal harbour behind breakwaters. It takes ships up to 312 m long, through a channel at least 11 m deep.
Harbours within 10 km
- Otaru Ko2 km from the centreMedium-sized harbour
What the live map can see
In 24 hours of AIS recorded Oct 12 – 19, the map heard no ship within 10 km of Otaru Ko: the receivers TAKIP draws on don’t reach here, so its ships won’t show.
Good to know
- NGA’s World Port Index rates a harbour by its area, facilities and wharf space when it was last surveyed, not by its traffic, so a busy terminal can be rated small. Where it doesn’t know about a facility it says so, and only what it marks as there is listed here.
- AIS is heard by receivers on shore, so coverage follows where they are: ships far out at sea, or off coasts without one, don’t show. Warships and some others switch it off, and a ship’s type and destination are typed in by its crew.
- Harbours from NGA’s World Port Index (Pub. 150), downloaded on Oct 19, 2026. The major ports and chokepoints are the map’s own reference list.
How the layers work, where their data comes from and what they can’t tell you: Live ship tracker, Shipping chokepoints