The Northwest Pacific Ocean is a broad ocean influenced by two major currents: the cold Oyashio Current flowing southward and the warm Kuroshio Current flowing northward. In this region, radiolarian microfossils are well preserved in deep-sea sediments, making them valuable proxies for reconstructing past oceanic conditions. Here, I present radiolarian assemblage census data covering the equatorial to subarctic Northwest Pacific. This dataset, comprising 122 samples, can be valuable not only for estimating Sea Surface Temperature but also for conducting further ecological analyses using advanced statistical methods. These data are published in Matsuzaki and Itaki (2017, Paleoceanography) and Matsuzaki et al. (2025, Progress in Earth and Planetary Science).