Indonesia is once again turning its attention to an ambitious coastal defense plan. The Giant Sea Wall, a massive infrastructure project, has returned to the top of President Prabowo Subianto’s priority list as concerns grow over sinking land and rising sea levels along the northern coast of Java.
The government, through the Java Northern Coast Management Authority Agency (BOPPJ), estimates the project will require investment of up to US$100 billion, or around Rp1,681 trillion, based on an assumed exchange rate of Rp16,815 per US dollar. It is a staggering figure, reflecting the scale of what is being planned.
According to BOPPJ Head Didit Herdiawan Ashaf, the sea wall will span approximately 535 kilometers. Construction is set to begin in stages from Banten in the west, continue through West Java, and stretch all the way to Gresik in East Java. The structure is designed as a long-term safeguard for areas that serve as the backbone of Indonesia’s economy.
President Prabowo has framed the project within the broader context of climate change. “As the largest archipelagic country in the world, Indonesia has already felt the direct impacts of climate change, especially the threat of rising sea levels. On the northern coast of the capital, sea levels are rising by five centimeters each year. Imagine what will happen in the next 10 to 20 years,” he said during the 80th United Nations General Assembly on Tuesday (23/9/2025).
The National Development Planning Agency, or Bappenas, has also explained why the project is considered urgent. Minister of National Development Planning and Head of Bappenas Rachmat Pambudy emphasized that much of Indonesia’s economic activity is concentrated along the northern coast of Java. Currently, 56 percent of the country’s Gross Domestic Product is generated on the island of Java.
““70% of that 56% [of GDP on Java Island] is on the Northern Coast. And out of 100% of our GDP, 20% is in the Greater Jakarta area, and 18% is in Jakarta,” Pambudy said during the National Urban Policy agenda on Monday (15/9/2025).
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For the government, protecting this corridor means protecting the nation’s economic core. “So safeguarding infrastructure in the Northern Coast of Jakarta means safeguarding Indonesia,” he stated.
Even so, the Giant Sea Wall has never been free from controversy. Debate has followed the proposal for years. Economists question the financial burden. Environmental groups warn of potential ecological damage.
In its early stages, several officials from the Coordinating Ministry pointed out that the project had not yet been listed as a National Strategic Project. They said further comprehensive feasibility studies were needed, including assessments of environmental impact and detailed cost analysis.
There is also recognition that land subsidence cannot be solved by seawalls alone. Officials have stressed the importance of additional mitigation efforts, particularly reducing excessive groundwater extraction. Public and environmental groups remain concerned that a structure of this magnitude could disrupt coastal ecosystems and alter natural sedimentation patterns along the shoreline.
As the plan moves forward, the Giant Sea Wall stands at the intersection of urgency and uncertainty. It represents both a bold attempt to shield Indonesia’s economic heartland and a project that must answer tough questions about cost, impact, and long-term sustainability.
