In this 21st century, sustainability is an issue of extreme importance for humankind. As regards drinking water, a serious shortage is expected by 2050, when one-third of the world's population is predicted to lack sufficient access to drinking water. In the field of concrete, billions of tons of freshwater is consumed annually for mixing, curing and washing concrete. Seawater is presently not permitted to be used for these purposes. Active use of seawater in the field would contribute to more effective use of freshwater resources.Based on this social situation, JCI （Japan Concrete Institute） set the committee to research the possibility of seawater usage in concrete production, such as concrete mixing, concrete curing etc. Based on the results, issues surrounding the use of seawater and possible solutions are proposed. In this report, readers are expected to find the committee activities and committee attitude. In Kyushu University, recent several years, a research on concrete characteristics mixed with seawater is continued. In this paper, a discussion on seawater utilization as concrete mixing water based on the research results is also summarized.Actually, this paper is a summary paper of three presentations by authors, Hamada, Patah, Harahap, in the JSCE conference held in Toyama, 2018 October.