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Sunda Shelf: Southeast Asia at lower sea level
The Sunda Shelf is the shallow continental shelf of western Southeast Asia. At glacial low sea levels, large areas of this shelf were exposed and major islands formed parts of a more connected landmass.
Which lands were connected?
Reconstructions show broad connections between the Malay Peninsula, Sumatra, Java and Borneo during low sea levels. The shape of that exposed land changed as seas rose and fell; it was not a permanent continent with one fixed outline.
Why Sunda was not joined to Australia
Deep-water passages in Wallacea remained between the Sunda and Sahul shelves. A larger exposed Sunda does not imply a continuous land route to Australia. Studies of Sahul’s settlement therefore consider water crossings as well as travel over land.
References: Voris (2000) — Maps of Pleistocene sea levels in Southeast Asia: shorelines, river systems and time durationsSalles et al. (2024) — Physiography, foraging mobility, and the first peopling of Sahul
What this map leaves out
The exposed shelf does not show ancient forest cover, river channels or human movement. Modern elevation and a single global sea level are insufficient to reconstruct those features. Use this view to compare broad shelf geometry, then consult regional studies for environmental and archaeological questions.