Diving & Travel Guide to Pulau Sangiang & the Sunda Strait

Pulau Sangiang and the Sunda Strait represent a unique and historically significant diving region at the narrow seaway connecting the Java Sea to the Indian Ocean, positioned between Java and Sumatra with the legendary volcanic island of Krakatoa (Krakatau) as its dramatic centerpiece. The Sunda Strait is one of the world's most important maritime chokepoints, and its strong tidal currents create nutrient-rich conditions supporting healthy coral communities on the volcanic substrates and limestone outcrops that characterize the underwater landscape. Pulau Sangiang itself is a small, uninhabited island with exceptional coral reefs on its western and southern shores, where the strong currents deliver a constant supply of plankton supporting vibrant soft coral gardens and large barrel sponges. The diving ranges from gentle reef slopes suitable for all levels to more challenging drift dives along the volcanic walls and submerged pinnacles created by the region's explosive geological history. The legacy of the 1883 Krakatoa eruption is visible underwater in the form of dramatic volcanic formations, coral-encrusted lava flows, and the ongoing process of marine colonization on the newer volcanic substrates. The Anak Krakatau (Child of Krakatoa) volcano, which continues to grow from the caldera of the original eruption, provides a spectacular backdrop for surface intervals and occasional snorkeling on its black sand beaches. The Sunda Strait also holds significant WWII history, with several shipwrecks from the 1942 Battle of Sunda Strait lying at diveable depths, including the USS Houston and HMAS Perth, both of which are considered war graves and attract technical divers. For the recreational diver seeking a combination of volcanic geology, healthy reef diving, and historical significance, the Sunda Strait region offers a compelling and accessible destination from Jakarta and the Banten coast.