Lombok Strait: the deep-water alternative to Malacca

The Lombok Strait, between the Indonesian islands of Bali and Lombok, is the main deep-water alternative to the Strait of Malacca. It is more than 150 metres deep and at least about 11.5 miles wide, so it takes fully laden very large crude carriers and the largest bulk ships that Malacca's roughly 25-metre channel cannot. Together with the Makassar Strait to the north, it forms one of Indonesia's designated archipelagic sea lanes and links the Indian Ocean to the Pacific and the South China Sea.

Lombok matters for two kinds of traffic. It is already the normal route for Australian iron ore, coal and LNG sailing to China, Japan and South Korea. And it is the fallback for Gulf crude bound for Northeast Asia if Malacca were closed or became too costly. Modelling by Singapore's S. Rajaratnam School of International Studies (RSIS) puts the extra cost of a Malacca diversion at about $472,000 per voyage in fuel and time, adding one to three days of sailing. The limit is capacity: Lombok handles a few thousand transits a year against more than 100,000 through Malacca, without comparable traffic management, anchorages or bunkering.

Key numbers

What flows through the Lombok Strait

Bulk commodities from Australia dominate: iron ore from the Pilbara and coal from the east coast heading to Chinese, Japanese and Korean steel mills, plus LNG from Western Australia and the Northern Territory. Deep-draught tankers carrying Gulf crude to Northeast Asia also use the Lombok and Makassar route when they are too large to transit Malacca fully laden, rather than lightening cargo at Singapore. Official annual transit counts for Lombok are not published in a form comparable with Malacca's ⏳.

Who depends on the Lombok Strait

Australia's export industries depend on it most, together with the Northeast Asian buyers of Australian ore and gas. Japan takes about 40% of its LNG from Australia, and much of it sails through Indonesian waters on this route. See Japan's LNG imports. China depends on Lombok as the only credible sea route for Gulf crude if Malacca were blocked. See China's crude oil imports.

Indonesia, as the coastal state, controls the lane. That leverage became visible in April 2026, when Indonesia's finance minister floated a transit levy on its straits before withdrawing the idea within days.

Alternatives and bypass routes

Strait of Malacca. The shortest route between the Indian Ocean and the South China Sea, but too shallow for fully laden VLCCs and the most congested strait in the world.

Sunda Strait. Between Java and Sumatra; shallower, with a minimum depth near 20 metres and strong tidal currents, so it serves smaller ships rather than supertankers.

Around Australia. Possible in principle for traffic to the Pacific, at a cost of many extra days.

Historical incidents

Assets and companies exposed

Australian exporters of iron ore, coal and LNG, such as BHP, Rio Tinto, Fortescue, Woodside, Chevron and INPEX, whose Asian deliveries use the route.

Asian steelmakers and utilities buying Australian ore and gas.

Tanker owners operating VLCCs on Gulf to Northeast Asia routes, who would absorb the cost of any Malacca diversion.

Indonesia, as coastal state and provider of navigation services. This entry is descriptive: the encyclopedia does not publish recommendations.

What to watch

• Malacca congestion and security, which decide how much traffic would shift to Lombok.
• Indonesian policy on transit fees or navigation charges in its archipelagic sea lanes.
• Australian export volumes to Northeast Asia.
• IMF PortWatch transit data for Indonesian straits.

FAQ

Where is the Lombok Strait? Between the Indonesian islands of Bali and Lombok, linking the Indian Ocean to the Java Sea and, via the Makassar Strait, to the Pacific and the South China Sea. It is one of Indonesia's designated archipelagic sea lanes.

Why do supertankers use the Lombok Strait? Because it is deep enough. At more than 150 metres, it takes fully laden VLCCs that are too deep for the Strait of Malacca, whose channel is roughly 25 metres deep in its shallowest parts.

Is the Lombok Strait an alternative to Malacca? Yes, but not at scale. It adds one to three days and about $472,000 per voyage, according to RSIS, and it lacks the traffic management and port services to handle more than a small share of Malacca's 100,000-plus annual transits.