One of the forms of sustainable mobility is the public bicycle system. As the bike became more and more attractive to end users, the need for the development of public bicycle services emerged. Public bicycle service has developed through several generations and it is expected to develop further. Today it becomes an increasingly popular form of public transport in the cities of the world, which allows bicycle rental to users in the immediate area of the city. One of the world's leading public bicycle operators in the world is NextBike, founded in Germany in 2004, which also came to the Republic of Croatia in 2013, where it has 20.000 users. The advantages of this system have been recognized by some cities in the Republic of Croatia such as the city of Šibenik and Zadar whose residents and tourists are increasingly using this form of transport. The system of public bicycles in the city of Šibenik and the city of Zadar will be presented in order to gain insight into the amount of usage of the public bicycle system as one of the forms of sustainable mobility. The research has shown that a significant share in the total number of users of this service are tourists, that the average time of bicycle rental is about 30 minutes, and that residents of Sibenik compared to the city of Zadar have recognized the benefits of public bicycle services, regardless of the more unfavorable terrain configuration and transport infrastructure.