This final thesis explores and applies the General Transit Feed Specification (GTFS) standard for integrating maritime public transportation with land services in the northern Adriatic region. The introductory part emphasizes the importance of mobility in today's society and describes how technology, such as Google Maps, facilitates trip planning and provides information about public transportation. The main part of the thesis thoroughly analyzes the GTFS standard, providing descriptions and meanings of each component of this data format, including carrier information, stops, routes, trips, trip sequences, and the calendar. The difference between static and dynamic GTFS is also explained. Furthermore, the thesis describes the methodology of creating GTFS for maritime public transportation. It explains how data is collected, how the database structure is created, and data is entered, emphasizing the importance of data validation to ensure the accuracy and reliability of GTFS. Moreover, the integration of GTFS with the traffic model is explored using the example of the public maritime transportation network in the northern Adriatic region. Through the application of this model, it is possible to analyze and predict the effects of integrated services on traffic and travel. The goal of this work is to test the functionality of the model and obtain results that will aid in better understanding and planning of public transportation in the northern Adriatic region. Implementing GTFS in maritime public transportation would allow passengers to access accurate information about ship lines, routes, stops, and schedules, thereby improving the travel experience and facilitating trip planning for public transportation users.