This paper presents the design and implementation of Internet-based message transfer agent via INMARSAT-C between the land and ship for the convenient message transfer service using the Internet mail or Web. In order to achieve these purpose, overall system configuration for communication between the land and ship, agent modules and database for managing transmission and receiving data are described. For the validity evaluation of this paper, message parsing, database, message format and X.25 interface modules are implemented and tested. Based on the result, the capabilities of ship automation system and ownship database access are discussed.