Dear Colleagues, On behalf of the Local Organizing Committee, the International Program Committee, and the International Steering Committee, we sincerely invite you to the 12th International Conference on Tritium Science and Technology (Tritium 2019), in Busan, Korea, from April 22 to 26, 2019. The event is organized by the National Fusion Research Institute (NFRI), which leads fusion research and technology development in Korea. This conference will be hosted in Busan, well-known as Republic of Korea’s second-largest city and its biggest harbor city, which was a temporary capital during the Korean War. With beautiful natural scenery and world-class infrastructure, the city will offer participants an experience of the charming mixture of old and new. Tritium 2019 includes invited, oral and poster presentations as well as industrial and R&D exhibitions. It is our sincere hope that all participants will actively share the latest developments and pending issues in the field of nuclear fusion and tritium science. We look forward to your participation and scientific contribution to make Tritium 2019 a great success!