The Makassar Strait is an Indonesian maritime territory that has an important function not only for Indonesia, but also for other countries that use the Makassar Strait as their sea transportation route. The urgency of the security of the Makassar Strait itself is also driven by the plan to move the Indonesian Capital City to the Nusantara Capital City in East Kalimantan, more precisely in the Penajam Paser Utara Regency and Kutai Kartanegara Regency. This study will use the concept of maritime security according to Chris Rahman as the basis for research on Indonesia's strategy in securing the Makassar Strait. By using qualitative research methods, the author will focus on collecting data through literature studies, to answer the research question "what is Indonesia's defense strategy in securing the Makassar Strait in 2019-2024?". Using the concept of maritime security from Chris Rahman, this study found several efforts that have been made by Indonesia in securing the Makassar Strait, in accordance with the 5 approaches introduced by Chris Rahman regarding maritime security, namely (1) security of the sea itself; (2) Ocean Governance; (3) maritime border protection; (4) military activities; (5) security regulation of the maritime transportation system.