Japan will begin developing high-precision nautical charts for five strategically important waterways across Southeast Asia as part of a broader effort to safeguard maritime trade and reduce dependence on traditional shipping corridors.
According to the Yomiuri Shimbun, the project will focus on the Molucca Passage and Ombai Strait in eastern Indonesia, the Sunda Strait in western Indonesia, and the Surigao and Balabac Straits in the Philippines. Each survey will cover roughly 100 square kilometres and include hydrographic mapping, seabed studies and the installation of navigational aids.
Japan’s Foreign Ministry will carry out the work in partnership with Indonesia, the Philippines and Timor-Leste (East Timor), with the resulting charts expected to be published by the coastal states. Estimated to cost ¥2 billion (approx. $12.3 million), or ¥400 million ($2.46 million) per strait, the initiative will be financed through Japan’s Official Development Assistance (ODA) programme and is expected to be included in the fiscal 2027 budget.
The move comes weeks after tensions in the Middle East renewed concerns over the vulnerability of maritime chokepoints. Although the Strait of Hormuz remained open during the Iran-Israel conflict, the possibility of disruption highlighted how quickly energy supplies and global shipping could be affected.
For resource-poor Japan, which imports nearly all of its crude oil, ensuring alternative sea routes has become an economic and strategic priority.
According to the Foreign Ministry, more than 80% of Japan’s oil imports from the Middle East pass through the Straits of Malacca and Singapore, making them among the world’s busiest maritime corridors. Should those routes become inaccessible due to conflict, accidents or natural disasters, shipping could be redirected through the Sunda, Molucca and Surigao straits.
However, these waters have an abundance of reefs, shoals and narrow passages, and many existing nautical charts remain outdated. High-precision mapping would improve navigational safety while reducing risks for commercial shipping operating along these alternative routes.
The project also carries a broader strategic dimension. Several of the waterways lie close to areas where China’s naval and coast guard presence has steadily expanded in recent years. While Japan has framed the initiative as one of maritime safety and disaster preparedness, better hydrographic data will also strengthen the maritime capabilities of Southeast Asian partners by improving coastal surveillance, search-and-rescue operations and efforts to combat illegal fishing.
The initiative underscores Japan’s evolving approach to development assistance, which increasingly incorporates security objectives alongside economic cooperation. Under its Free and Open Indo-Pacific (FOIP) vision, Tokyo has expanded support for maritime infrastructure and capacity-building across the region as competition over critical sea lanes intensifies.
For India and other Quad partners, resilient sea lines of communication remain central to Indo-Pacific security. Japan’s latest initiative complements wider efforts to diversify shipping routes, strengthen maritime domain awareness and reduce dependence on a handful of strategic chokepoints.
