OpenSeaMap
OpenSeaMap is a free, worldwide nautical map that adds sea-related information to OpenStreetMap. It is a community project created by members of the OpenSeaMap and OpenStreetMap communities. The map is available online at map.openseamap.org and openseamap.org, and it can be downloaded as an electronic chart for offline use. The content is licensed under CC BY-SA for the map and ODbL for the data. Reading the map is free, and registration with a verified email is required to contribute data.
OpenSeaMap shows navigational aids such as lighthouses, buoys, and other marks, along with ports, marinas, docks, fueling stations, and other harbor facilities. It also provides weather information for many areas, with wind data, air pressure, and forecasts for several days. Each harbor can have a Meteogram with detailed wind and weather forecasts for up to eight days.
The project aims to cover the world and is translated into several languages. Depth data are not a core feature yet, but there are plans to add bathymetry in the future. The base map comes from OpenStreetMap, with extra nautical layers on top. Data can be accessed by other software through a standard interface, and updates appear worldwide after data are added.
OpenSeaMap started in 2008 at an OpenStreetMap developer conference and launched in 2009. It grows through volunteers who expand coverage of seas and freshwater bodies. It is useful for planning sailing trips and as a guide for tourists, but it is not a replacement for official nautical charts.
This page was last edited on 2 February 2026, at 22:42 (CET).