Preface. 1. Assessment methodologies for submarine groundwater discharge (M. Taniguchi, W.C. Burnett et al.). 2. Radon tracing of submarine groundwater discharge in coastal environments (W.C. Burnett, J.E. Cable, R. Corbett). 3. Chemical characteristics of submarine groundwater seepage in Toyama Bay, Central Japan (J. Zhang, H. Satake). 4. Prospects of engineering applications of submarine-groundwater-discharge research in Japan (H. Miyamoto, T. Tokunaga). 5. Evaluation of sea water intrusion accompanying the coastal coal mine excavation in the Joban coalfield area, Japan (J. Shimada, K. Kojima et al.). 6. Natural tracing in karst aquifers (M. Monnin, M. Bakalowicz). 7. Abundance and viability of subsurface microbial communities in sedimentary and igneous rock aquifers (Y. Murakami, Y.Fujita et al.). 8. Stable isotopic compositions of bacterial light hydrocarbons in marginal marine sediments (F. Nakagawa, U. Tsunogai et al.). 9. Submarine hydrothermal activity in coastal zones (T. Gamo, G.P. Glasby). 10. High permeability of young oceanic crust constrained by thermal and pressure observations (K. Wang, E. Davis). Index of Authors. Subject Index.