The number of mega containerships operated by the major container shipping operators has reached a significant level in their fleet. However, the technical and physical insufficiencies of container ports do not allow handling of the latest generation mega containerships. The challenges of handling ultra-large container vessels (ULCV), especially in the main container lines, force port authorities to produce new port solutions. Offshore container port system (OCPS) is one of the recently proposed solutions to deal with the challenges of handling ULCVs more efficiently. These structures provide flexibility in eliminating operational difficulties arising from ULCV dimensions, while also helping to eliminate navigational constraints such as bridge and canal passages, and water draft. This article applies a research approach designed to evaluate the application of an OCPS in a particular geographical region. Based on this application, this research focuses on economic changes likely to arise as a result of the integration of ULCVs and OCPS into the existing container transport network. Accordingly, the developed container transport network model covers both the main route and the short sea shipping (SSS) leg, considering the offshore container port as a hub. In essence, this research is proposing an alternative port system and its associated container transportation network, for those ports that are currently unable to handle ULCV. To solve the problem, the paper presents a mixed- integer linear program model. It utilises a number of different decision variables and constraints in the process of making the model more realistic. Extensive numerical experiments based on realistic Asia-North America (West Coast) container shipping operations show that the model can be solved by Excel Solver. A case study for a container shipping network, using a set of 10 North America (West Coast) container ports linked to Asian markets, is presented herein. However, the robustness of the conclusions is subject to the uncertainty of the used values and the hypotheses made. Even though, the results can serve as an argument to strengthen the belief that the offshore container port concept can be considered as an alternative to conventional container ports.