The Djuanda Declaration was motivated by a regulation issued by the Dutch colonial government, Territoriale Zee en Maritieme Kringen Ordonantie (Territorial Sea and Maritime Circles Ordinance) of 1939. The ordinance stipulated that the sea width for each island in Indonesia is 3 miles, which was determined by a baseline drawn according to the water line on the island's contour or tidal. Thus, each island only has 3 miles of coastline. This means that the islands in the archipelago are separated from each other by the surrounding sea. After 3 miles from the coastline, the sea becomes a free ocean that can be entered by foreign ships. The regulation is certainly unfair to Indonesia and benefits foreign parties.
Therefore, the Djuanda Declaration was made, stating that the width of Indonesia's territorial sea was 12 miles from the line connecting each of Indonesia's outermost islands, and became one unit with the new territorial line. The declaration stated that Indonesia adheres to the principle of an archipelagic state so that the inter-island seas are the territory of the Republic of Indonesia and not free areas.
Even though the Djuanda declaration had been promulgated in 1957, at the time it received great opposition from several countries. The world only recognized this rule a few decades later. After making various measures over the years, the international community was finally willing to accept the concept of the declaration in 1982 through the United Nations Convention on the Law of the Sea (UNCLOS) at a meeting in Jamaica. However, the Indonesian Law of the Seas was only officially recognized by the international community in 1994 after being ratified by 60 countries.
Even though the commemoration of Nusantara Day is not as well known as other national days, its meaning is very important. With the Djuanda Declaration, the Indonesian nation can secure all of its seas and the natural riches within them, counting 12 miles from each of Indonesia's outermost islands. The Indonesian seas are a very important means for inter-island relations because of its nature as an archipelagic country. Therefore, it can be said that the development, security, and sovereignty of the Unitary State of the Republic of Indonesia rests on maritime sovereignty.
Hopefully, Indonesia can continue to defend its maritime sovereignty by protecting it from claims by other countries, and preserving the marine environment so that it has sustainable benefits for the welfare of the Indonesian people.