The article traces the evolution of the Asia-Pacific security systems: the collective security system and the cooperative security system. The formation and the evolution of those systems are scrutinized, the factors behind their transformation are revealed, the influence of the mega-projects Indo-Pacific Region (IPR) and the Belt and Road Initiative (BRI) on both systems is clarified. The academic novelty of the paper stems from a synergy of analyzing the specificity of the Asia-Pacific security systems and the evolution of the Indo-Pacific Region and the Belt and Road Initiative, which has not been sufficiently explored to date. The authors argue that the IPR leads to a decrease in efficiency of both the US-led alliances and the ASEAN-led multilateral venues, while the BRI, bringing a dividing effect on relations between the members of US-led “hub-and-spoke system”, improves positions of ASEAN as the coordinator of ARF, ADMM+8 and the EAS. As a result, the foundations for the neutral and inclusive agenda of multilateral negotiations as a key factor of the ASEAN-led cooperative security system are strengthening.