Japanese Technical Cooperation Project for Promotion of Regional Initiative on Solid Waste Management in Pacific Island Countries II is a collaboration of JICA and SPREP to handling with solid waste pollution in Pacific Island Countries. This study aims to discuss Japan and the Pacific Cooperation in handling solid waste in Pacific island countries through J-PRISM II. This study uses a qualitative method with a descriptiveanalytical approach with primary and secondary data collection techniques. Primary data is by conducting interviews with related parties in SPREP. Furthermore, secondary data is collected through journals, newspapers, and reports from official internet sites, by using two concepts to assist and strengthen this research, namely the concept of Environmental Security and International Cooperation. This study concludes that cooperation between Japan and the Pacific through the J-PRISM II Project in handling and addressing the solid waste in the Pacific region has a significant impact on better plastic waste management. Through the development of monitoring systems, skills exchange programs, disaster waste management and, 3R + Return systems.