Every year, the alluvium deposited by the Danube increases the width of the Delta by around 40 meters, making it extremely dynamic. Near Tulcea, the Danube is divided in three river branches before it flows into the Sea: Chilia, Sulina and Sfântu Gheorghe (Saint George), but many other channels split the Delta into areas with reed, marshes and forests, some of which are flooded during the spring and autumn.

About 44 km off the coast of the Danube Delta lies Snake Island, a territory which has been claimed by both Romania and Ukraine but is currently administered by Ukraine.

In 2004, Ukraine inaugurated work on the Bistroe Channel that will provide a navigable link from the Black Sea to the Ukrainian section of the Danube Delta. The European Union urged Ukraine to shut it down, because it will damage the wetlands of the Delta. The Romanian side, committed to protecting the delta, said they will sue Ukraine at the International Court of Justice.

In 1991, Danube Delta became part of the World Heritage List, and, together with 812 properties forming part of the cultural and natural heritage which the World Heritage Committee considers as having outstanding universal value.