International alliances (or strategic alliances) are combinations of global agreements between linear shipping companies. These agreements were signed in the mid-1990-es, and they include ocean carriers operating the main global routes. Alliances became a crucial phenomenon in shipping in the last few decades. In the past, the cooperation of linear shipping companies stipulated the coordination of prices and volumes. In the last two decades, global alliances of competing companies appear that distribute vessels to increase their operational efficiency and expand service areas. The character of these alliances changed over this period as described in this article. Besides, the authors formulated hypotheses that justify the key determinants impacting the success and efficiency of shipping company alliances. They also provide the results of reliability studies for the data impacting alliance efficiencies, such as the cross-company coordination, organizational training, alliance costs, its duration, and company size.