The safety assessment for MASS depends on the assumed use cases and ConOps. However, future MASS use cases remain diverse, making it difficult to establish prescriptive rules. This study aims to clarify future use cases by drawing on interviews with the Japanese maritime industry. Interviews were conducted with 21 domestic stakeholders to investigate expectations for MASS deployment over the next five years. Based on the insights obtained, representative use cases and ConOps were developed. In addition, the interviews revealed a range of technical and institutional challenges. This presentation contributes to establishing premises for future MASS safety assessment and discussion.