Approximately half of the Antarctic Ice Sheet's basement lies below sea level, and ice sheet retreat due to global warming will lead to the emergence of new ocean areas. However, the large gaps in sub-ice sheet topography are one of the biggest uncertainties in future predictions. The Antarctic RINGS project, promoted by SCAR (Scientific Committee for Antarctic Research) and COMNAP (Council for Conducting Antarctic Research), is an international framework that is efficiently and strategically combining observational resources from various countries to fill in these gaps and explore the future ocean.

During the 33rd Japanese Antarctic Research Expedition (1991-1992), a sediment trap mooring observation was conducted in the Southern Ocean, but the loss of equipment prevented any results from being achieved. Thirty-four years later, after securing research funding and with the cooperation of early career researchers, the 66th Japanese Antarctic Research Expedition (2024-2025) successfully installed a sediment trap mooring system along with new sensors that had not been developed at the time of the 33rd expedition. It is scheduled to be retrieved by the 67th expedition (2025-2026), aiming to clarify a actual processes of the carbon cycle in the Southern Ocean, East Antarctica.

ArCS III, Japan's flagship project for Arctic research, began in April 2025. This paper provides an overview of the history and characteristics of previous Arctic research projects in Japan, and then introduces how these will be developed in ArCS III and what initiatives will be implemented to achieve this.

The Northern Sea Route (NSR) has the potential to shorten sailing times between East and West, yet the economic model underpinning its development faces serious challenges. Russia has promoted the development of the route in conjunction with Arctic resource projects; however, Western sanctions and fiscal constraints have rendered future investment prospects increasingly uncertain. Although transport between Russia and China has expanded in recent years, broader utilization by the international shipping industry and the securing of sustainable financing remain difficult.