Ports are an important part of the transportation system and important trading centers where sea and land traffic meet. The Adriatic ports and other Italian ports are located on busy traffic routes. Through their trade with other European, African and Asian ports, they are internationally networked. Given the increase in traffic in this area in recent years, it is necessary for the ports to evaluate their performance. Performance evaluation is a tool that can help ports to obtain useful data on their performance and identify key factors that help them to position themselves competitively. This study compares the efficiency of container ports in two major European maritime transport areas, namely the Adriatic ports and other Italian ports, considering environmental aspects and port characteristics. In this paper, an improved non-radial Data Envelopment Analysis (DEA) method is used to calculate the overall efficiency of the ports and then analyze the differences in port performance. The reasons for the efficiency and inefficiency of the ports as well as the weaknesses and strengths are calculated using the proposed method for the compared ports.