The Lombok and Sunda Straits are emerging as critical alternative maritime routes to the congested Malacca Strait, particularly for deep-draft vessels carrying oil and LNG to China, Japan, Korea, and coal exports, with traffic volumes rising significantly in 2026.

Indonesia, as the sovereign state controlling these straits, must integrate them into its national maritime strategy with enhanced naval patrols, infrastructure, digital monitoring, and traffic management to address security and capacity challenges.

ASEAN needs to expand its maritime security framework (e.g., through the ASEAN Maritime Forum) to include these straits for joint patrols, intelligence sharing, and coordinated development, preventing external powers from dominating their security while supporting regional energy flows and economic stability.

The Strait of Malacca is perhaps the world’s most critical maritime chokepoint, carrying a third of global trade. Yet, other routes in Southeast Asia are increasingly important for global shipping and energy security. These are the so-called alternative routes, such as the Lombok and Sunda Straits, both of which are situated within the Indonesian territorial waters. As Malacca remains critical, Lombok and Sunda are developing into important maritime routes of their own, thus creating a strategic blind spot in ASEAN that puts Indonesia at the centre of the maritime competition.

The problem centres on the overemphasis given to Malacca, as the principal channel connecting the Indian Ocean and the South China Sea. The Malacca waterway is a very narrow passage of less than three kilometres in width at its narrowest point. It is always congested and becomes very vulnerable to potential piracy. Each year, around 90,000 vessels navigate through the Malacca waterway, including 16 million barrels of oil daily, accounting for around 30% of the world’s seaborne oil trade. Container traffic accounts for around 25% of global movements........

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