The objective of the research is to examine the role of Supply Chain Integration (SCI) which consists of; suppliers, customers, and internal integration in building customer loyalty. This study uses data from 308 top managers of Tuna Fillets SMEs Industries in Southeast Sulawesi Province, Indonesia as respondents. The research model was analyzed by using PLS-SEM. The research found that SCI had a significant direct effect on operational performance and customer satisfaction. The research also found that operational performance and customer satisfaction had some impacts on increasing loyalty of Tuna Fillets SMEs Industries customers. The results of the analysis also provide information that operational performance and customer satisfaction can be a mediator of the influence of Supply Chain Integration.