The CERDI-SeaDistance database contains bilateral maritime distances between 227 countries and territories. The relevant port(s) for countries with access to the sea is defined as the coastal region of a country which contains the highest number of shipping lines (landlocked countries are linked to the foreign port with the shortest road distance to its capital city). The length of the existing shortest sea route between the two ports is then computed; this represents the bilateral maritime distance included in the database, which also contains a few additional ancillary variables.
See the publication on HAL :
See the database : https://zenodo.org/record/46822#.VvFcNWMvyjp
Version : 2016-03-01