In 2024, Indonesia held simultaneous regional head elections on the same day across the country, in contrast to the traditional patterns of regional head elections held in succession. Simultaneous regional head elections were held to increase stability and efficiency. However, there are several drawbacks, such as creating a vacancy in regional head positions that necessitates the appointment of an acting head and even forcing some permanent regional heads to step down before their terms are up. This study examines the contradictions in the 2024 simultaneous regional head election policies using the antinomy perspective. The study reveals two fields of legal antinomies under the policy of simultaneous local elections: norms and principles. This conclusion comes from normative secondary data analysis utilizing statutory and conceptual approaches. The legal antinomy on norms arises from a contradiction within the Regional Head Election Law. Article 201 Paragraph (8) orders simultaneous local elections for government stability. On the other hand, Paragraph (9) allows the appointment of acting heads of regional government, which has the potential to cause administrative, political, and social instability. In this context, a paradox emerges between the intended goal of stability and the potential for instability resulting from the policy. The legal antinomy on principles appears in the conflict between budget efficiency (expediency principle) and legal certainty. The goal of saving costs clashes with the principle of legal certainty because the fixed term of office for elected regional heads is set by law. This study helps better understand the challenges of moving from conventional to simultaneous local elections.