Purpose: Despite being the core of commercial and legal research in international commerce and trade, this paper contributes to establishing the identity of international commerce by dissecting Incoterms, which has been emphasized only by changes in rules due to practical functions and revisions. Research design, data, and methodology: The limitations and implications of Incoterms were determined from a literature search and analysis of statistical data. Results: In general, the common law that appears in international commercial transactions is called Lex Mercatoria, which distinguishes it from the common law. Among the formal transaction conditions of Incoterms, the FOB, CFR (C and F), and CIF conditions are used repeatedly, so they have been established as Lex Mercatoria and have become de facto standards of the trading industry and can be said to be the true Lex Mercatoria. Conclusions: Before Incoterms can be recognized as Lex Mercatoria, it must be established in the industry as a business practice to expand the use of existing Incoterms rather than periodically revising them. Moreover, the ICC must abandon the lingering desire to commercialize the arbitrary rule, Incoterms, and contribute to forming a new Lex Mercatoria through active promotion and marketing.