The objective of the Study on Cost-Time-Trade-offs Between Air and Sea Freight Transportation from the Port of Chennai, India to the Port of Rotterdam, Netherlands is to determine the methodology incorporated by businesses when deciding between utilizing air versus sea freight. These decisions are influenced by numerous variables including the cost of transportation, transit time, and customer demand. In an international logistics perspective, how a company chooses to transport goods will ultimately affect the overall efficiency of their supply chain, the satisfaction of their customers, and the company's delivery performance. As one of the largest commercial routes connecting Indian products to European markets, selecting the appropriate mode of transportation has important implications for the company's operation. The main objective of the study is to analyse how logistics companies balance transportation cost, delivery speed, and shipment urgency while choosing between air and sea transport. The research is based on primary data collected from 60 respondents working in logistics, freight forwarding, shipping, and supply chain management through a structured questionnaire. Convenience sampling was used for data collection. The IBM SPSS program was applied to analyse the following methods: descriptive statistics, percentage analysis, weighted average ranking, chi-square testing, correlation analysis, regression analysis, and ANOVA. Based on this research, results show that air transport is preferred to deliver items that need to be shipped urgently or quickly because it takes less time for delivery and can rely on the reliability of the delivery itself. In contrast, sea transport will usually be the preferred mode of shipment for normal and bulk items due to its lower cost than air transport. In terms of influence on transportation decisions, cost is by far the most important factor, followed by urgency of demand and time in transit. Ultimately, the research suggests that to improve both logistics performance and customer satisfaction, there must be a strategic balance between the cost of transportation, how quickly the transportation can be completed, and consumer demand for products when planning for transportation services between Chennai, India and Rotterdam, Netherlands.