Following the success of the last conference held in Guilin, China, in 2015, the Japanese Geotechnical Society and ISSMGE TC106 are pleased to host, in this great tradition of conference series, the 7th Asia-Pacific Conference on Unsaturated Soils (AP-UNSAT2019) in Nagoya City, the geographical center of Japan. The organizing committee of AP-UNSAT2019 also hope that all events during the conference provide an easy-access bridge between theoretical research and practical applications related to unsaturated soils. In particular, young researchers and engineers dealing with unsaturated soils from Asia-Pacific region and beyond are warmly encouraged to attend the conference and submit their papers. Well-documented case histories from the region are also particularly welcome.