International commercial courts are ‘international’ in that they perform functions that may be characterized as international. First, all ICommCs of the three categories presented in the chapter are domestic courts for international commercial disputes, or international business, more broadly defined. Second, they allow the internationalization of domestic legal orders by helping a jurisdiction attract foreign capital, and become a global and regional dispute resolution hub. ICommCs’ functional internationalism spills over into their organizational and procedural design. While ICommCs may be seen as hybrid institutions – between the national and the international, the public and the private, the formal and the informal – the chapter brings to light the new institutional mechanisms of interoperability between them and other dispute resolution fora – domestic courts, international commercial arbitration and international courts and tribunals. The functional interoperability will eventually determine the durability of ICommCs.