The South China Sea is one of the most contested regions in the world. Tensions are escalating between China and the littoral states. China’s growing assertiveness and continued militarisation of the area is raising security concerns amongst the other states. This heightened feeling of insecurity has defaulted into an arms race, where the states are fortifying and increasing their own military capabilities. In short, the South China Sea dispute is a territorial dispute and maritime dispute between China, Taiwan, the Philippines, Vietnam, Brunei and Malaysia.

In some cases, the claimants have overlapping claims of the South China Sea. China, Vietnam and the Philippines are the three states that have the most expansive claim within the disputed territory. China is the only claimant that places their territorial claim on historic rights. The South China Sea dispute it is not only about sovereignty, but it is also driven by possibility of a vast amount of resources beneath the seabed, which can be used to supply the claimants growing need for natural resources and fuel their economy.

The purpose of this thesis is to examine China’s behavioural change in the South China Sea dispute and analyses the systemic variables that have attributed to this gradual change. The thesis draws upon a structural realist framework to analyse the three basic assumptions of structural realism: balance of power, security dilemma and national interest to the see the extent of the impacts. It also examines the changing dynamics between the United States and China to see if it has had any effect on their actions.

The analysis will be conducted as a mixed methods case study to gain an in-depth knowledge about such a complex social phenomenon. The case study was limited to a time span from 2010 to 2018, as the academic literature cites 2009 and 2010 as the origin of Chinese assertiveness. From the analysis it can be concluded that the variables have had an impact on China’s conduct. The systemic factors have facilitated China’s rise within the international system. China now hold revisionists intentions and thereby the assertive and aggressive behaviour will continue until they gain full control of the South China Sea. If China continues to modernise their military forces and increasing their relative capabilities, they will be able to drive the United States out of the South China Sea completely.