The 1st International Conference on Optical and Terahertz Communications and Future Networks (OTCN 2025) will be held in Tokyo, Japan, from September 26 to 28, 2025. This conference serves as a premier platform for global researchers and industry experts to exchange cutting-edge insights on optical communications, terahertz technologies, future network architectures, and their transformative applications. The conference will highlight groundbreaking research, technological advancements, and industry trends, bridging theoretical innovation to real-world implementation. We warmly invite submissions from scholars, engineers, and industry leaders worldwide to shape the future of communication technologies.