This paper aims to propose alternative modes of transport for Thailand-Myanmar’s cross-border trade at Ranong Province. The intermodal transport concept which connecting coastal shipping to road transport is applied to this study. The transport cost, which comprises of financial cost and environmental cost, is analyzed in aspect of macro view. The result shows that, when only the financial cost is analyzed, single mode of road transport would cost cheaper than intermodal transport while the latter would cost cheaper when environmental cost is included. To enhance sustainable transport and reveal its real cost, this paper suggests that Thai Government should promote this alternative by including environmental costs in the truck license fees. Furthermore, the related private sector such as coastal shipping lines, port operators, truck companies and exporters should cooperate closely on strategy planning.