Purpose: Container fill rate is an important indicator of transport efficiency, as underutilised container capacity can lead to unnecessary transport movements, higher costs and increased environmental impact. Previous research has mainly addressed container fill rate from a technical optimisation perspective, focusing on how goods can be arranged inside containers. However, less attention has been given to how organisational processes, information quality and coordination between actor’s influence fill rate before the physical loading takes place. The purpose of this study was therefore to analyse how manufacturing companies’ internal and interorganisational processes should be structured to improve the fill rate in intermodal container transport.Methods: The study was conducted as a qualitative single-case study within a manufacturing company. Data were collected through semi-structured interviews, observations and document studies. The interviews included actors involved in order handling, transport planning, warehouse operations and logistics management. Observations were used to study how planning assumptions were translated into physical loading practice, while documents and system-related material provided insight into formal processes and available planning information. The empirical material was analysed thematically and interpreted through an analytical framework based on logistics planning conditions, information and uncertainty, organisational processes and decision-making, and interorganisational coordination.Results: The findings show that container fill rate is not only determined by the physical loading activity, but by a sequence of decisions and handovers before loading. Pallet characteristics, especially stackability, strongly affect usable container capacity. However, this information was not systematically available in the planning systems, which created uncertainty and encouraged conservative planning. The study also identified a gap between planned and actual loading, as planning tools and loading execution were not fully aligned. Invoicing and customs documentation created process lock-in, making late adjustments difficult. In addition, responsibility for fill rate was fragmented across functions and actors, with limited use of key performance indicators or structured feedback between planning and execution.Contribution/Value: The study contributes by showing that fill rate should be understood as a process-based logistics performance outcome rather than only as a technical loading measure. It connects technical loading constraints with organisational and interorganisational process conditions. Practically, the study suggests that manufacturing companies can improve fill rate by making stackability and pallet information available in central systems, defining clearer ownership and follow-up, creating feedback loops between planning and execution, and introducing controlled flexibility before process lock-in occurs.