Underwater Archaeology or Marine archaeology is a interdisciplinary study which acts a bridge between humanities and the sciences. It is also termed sometimes as Underwater Archaeology or Nautical Archaeology. It can be defined as the "study of past seafaring from the material remains of the activities". There are number of port-towns and other habitational sites which existed in the past, but may be now under the sea due to relative changes in sea level due to any reasons. There are also several ancient historic shipwrecks in the coastal zone wrecked either by inexperienced navigation, storms or overloading. The main objectives of marine archaeology are to locate and explore submerged ancient port installations, sunken cities and architecture of shipwrecks etc., to reconstruct maritime history.
Submerged sites and sunken shipwrecks are our cultural heritage. It is critical for us to decipher the records and link the past with the present. The rampart developmental activities in coastal zone, may destroy the evidence of bygone civilization for ever. It is therefore imperative to make marine archaeological investigations mandatory in the coastal zone, where any kind of developmental activities are taking place such as development of ports, harbours, industry and tourism etc. In case if any kind of archaeological remains are found, they should immediately inform to archaeological authorities, because once the evidence is lost, it can never be recovered.
The cohesive and intensive efforts should be made by public in general and archaeologists in particular, not only to create awareness but also convergent with techniques in marine archaeology. A body to monitor and educate concerned organization from different countries for the purpose should be established.
Indian Ocean has witnessed the dawn of several Bronze Age Civilization around it; for instance Egyptian, Mesopotamian and Indus Valley in the 4th-3rd millennium B.C. where the evidence of overseas trade are also recorded. Around Christian Era Romans were very actively involved in overseas trade with India. This is already proved by the presence of several Roman Period sites along the Indian coast. Finally in the 16th century A.D. several European races such as the Portuguese, British, Dutch, French and Danish etc. came through sea, down to Africa, Madagascar finally to India. There are several archival records which suggest that a number of ships sank in the sea, which have now became a part of the cultural heritage of the respective countries. Apart from shipwrecks several ancient ports have also been submerged in the sea which needs our attention to unearth for educational and scientific purposes.
The marine archaeological researches have flourished in countries like UK, USA, Germany, Israel as also in the Indian Ocean countries like China, Indonesia, India, Thailand and Australia. This work has revealed cultural links and provided insight on ancient trade system and level of knowledge on ship building and navigation.
In India, Marine Archaeological explorations are undertaken at Dwarka, Bet Dwarka, Somnath, Lakshadweep, Vijaydurg, Goa on the west coast and Tranquebar and Poompuhar on the east coast of India.