巽他陆棚是东南亚的向东南方向延伸的大陆架。陆地部分包括了马来半岛、苏门答腊岛、加里曼丹岛、爪哇岛、巴厘岛及附近小岛屿。 覆盖区域约1.85百万km。海洋部分的深度很少超过50米，大部分深度甚至不足20米，这导致了强烈的海水流动的底部摩擦与强烈的潮汐摩擦。 巽他陆棚以陡峭的海底坡度与菲律宾、苏拉威西、小巽他群岛分隔开。

巽他古陆（英语：Sundaland）是一个生物地理学上的概念，指的是末次冰期由于海平面下降而在东南亚地区露出水面并连成一体的陆地。

巽他陆棚的海域是相对稳定的古准平原，低地震活动、低重力异常、没有活火山。

Geologically, the Sunda Shelf is a southeast extension of the continental shelf of Southeast Asia. Major landmasses on the shelf include the Malay Peninsula, Sumatra, Borneo, Java, Madura, Bali and their surrounding smaller islands. It covers an area of approximately 1.85 million km. Sea depths over the shelf rarely exceed 50 metres and extensive areas are less than 20 metres resulting in strong bottom friction and strong tidal friction. Steep undersea gradients separate the Sunda Shelf from the Philippines, Sulawesi, and the Lesser Sunda Islands.