The present article analyses the feasibility for design and implementation of Electronic Data Interchange (EDI) systems for documentary exchange between Bulgarian Black sea ports and economic operators. The concept of the Port Community System (PCS) is analysed as a necessary information exchange framework for implementation of EDI systems. The main economic operators are identified and their interactions within the port community system are formalised. A methodology for implementation of EDI system has been developed along with the main information flows. The benefits of EDI implementation are outlined as means for increasing ports competitiveness.