In the South China Sea (SCS), as indeed the wider Indo-Pacific, the EU is facing a deepening strategic rivalry between China and the US. In the SCS, China has been able to create physical realities in defiance of international law by constructing artificial islands in the attempt to sustain its claims to the disputed Spratly and Paracel archipelagos as well as expand its military projection deep into international waters. The US is still the predominant security player in the Indo-Pacific, but its military presence has an increasingly hard time shoring up American power in the SCS. The security dilemma between the great powers is threatening rules-based multilateralism, which runs deep in the veins of the EU and to a great extent defines its international posture.