Historically, Vietnam’s Northeast sea and islands are considered one of the country’s important locations and gateways for diplomacy and economic exchange with a crucial role in the country’s development and protection. The sea and island space also offer rich natural resources and great potential for economic development and the preservation of many unique cultural heritage sites. The country’s development based on industrialisation and modernisation has been heading towards exploiting and promoting the rich potential of the vast marine space. Based on analysing the geocultural, economic, and political position of Cô Tô Island in the Northeast sea and islands, the article focuses on clarifying the special role and position of Cô Tô Island in the implementation of the Vietnam Maritime Strategy, the strategy of protecting territorial sovereignty and strengthening national defence, and the socio-economic development strategy within international cooperation. Along with this, the article also portrays the role of Hạ Long, Vân Đồn Island, and other locations.