Indonesia has three legal systems. Thus experts dispute which one to use. Peter de Cruz’s opinion on worldwide legal systems makes it hard to classify Indonesia. This paper analyses the existence of Mixed Legal Systems in the world legal system and the consequences of adopting them in Indonesia to create Prismatic Mixed Legal Systems. This hermeneutical and dialectical inquiry uses comparative legal ideas. The study shows that the legal system is mixed, which leads to practical challenges owing to international relations, which influence each country’s legal system. Simple Mixed, and complex Complex describe this legal system blend. A simple Mixed exists between Civil Law and Common Law, while Complex Mixed includes religious or customary law. The Indonesian legal system focuses on “Prismatic Mixed Legal Systems” “Mixed” must be regarded as a constant process to select the “best” resources from diverse sources of the legal system based on balance. It is anticipated that those individuals who specialise in Constitutional Law in Indonesia would carry on with their research and development on the Indonesian legal system, primarily through comparative law studies. This effort is essential in the framework for the future development of the National Legal System and is principally dedicated to the investigation and creation of “Prismatic Mixed Legal Systems.”