The present investigation aims study the sustainability of the business model of the Portuguese SMEs operating in the B2B International market analyzing the influence of dynamic marketing capabilities and adaptive marketing capabilities in their international marketing performance. It will also analyze the moderating effects of Competitive Intensity within this international scenario. A quantitative study was developed, using a questionnaire as a research method. In total, 335 valid responses were collected from Portuguese SMEs in June 2020. To test the hypotheses, multiple hierarchical regressions were performed. As for the analyzes involving Competitive Intensity environments, namely low and high intensity, dummies were developed to evaluate the different effects produced by the capacities in the International Marketing Performance. This study shows the positive impact of the dynamic marketing capabilities and adaptive marketing capabilities on the international marketing performance of the surveyed companies, essentially from the product development management, supply chain management, vigilant market learning and open marketing. when in a low competitive intensity environment only dynamic marketing capabilities had a positive effect on performance, but in a high, competitive, intensity environment both dynamic marketing capabilities and adaptive marketing capabilities showed positive effects in relation to performance. This study innovates by bringing international marketing, through two marketing capacities, from the perspective of SMEs that perform B2B activities.