This study examines the criticisms of the principle of consensualism in immovable property transactions in light of international legal instruments, adopting a descriptive-analytical approach with a focus on the prevention of land registration and real estate crimes. An analysis of the United Nations Convention on Contracts for the International Sale of Goods (1980), the Vienna Convention on the Law of Treaties (1969), and the Rome I Regulation demonstrates that, although these instruments recognize the principle of party autonomy, they do not regard it as absolute. Rather, its validity is subject to mandatory rules, public policy, the protection of third-party rights, and legal certainty. Accordingly, the unrestricted application of consensualism to immovable property transactions may undermine the official registration system and facilitate crimes such as conflicting transactions, multiple transfers of the same property, forgery and misuse of informal documents, land grabbing, tax and debt evasion, and other land registration-related offenses. In addition to its legal function, official registration serves as a preventive mechanism that reduces criminal opportunities, protects third-party rights, enhances transparency of ownership, and strengthens economic security. Therefore, limiting the effects of consensualism in immovable property transactions is more consistent with the preventive approach reflected in international legal instruments, as well as with the requirements of public policy and legal certainty.