This dataset contains ocean currents, bathymetry, and others collected by ADCP, echo sounder, and other instrumentation from the research vessel Mirai in the Western Pacific Ocean. MR21-Ueki cruise is a part of study for short-term climate variability such as El Niño/Southern Oscillation (ENSO), Asia-Australia monsoon, Madden-Julian Oscillation (MJO), Boreal Summer Intra-Seasonal Oscillation and so on, and the improvement of the prediction skills for those phenomena. For that purpose, we conducted observations for variability of upper ocean and air-sea fluxes by a research vessel and moorings. The moorings also contribute to the internationally-coordinated Tropical Pacific Observing System (TPOS) for ENSO monitoring, and operational weather and seasonal prediction by the operational meteorological agencies in the world. We conducted mooring operations at 4 sites and comprehensive air-sea observation, which includes observations by the R/V MIRAI, wave gliders, surface drifters, profiling floats and moorings at around 13˚N 137˚E. This cruise is U.S. State Department MSR U2020-022 as part of the World Data Service for Geophysics and Oceanography. Data are in TXT, CSV, and image (PNG) formats. Data description and reports are in PDF.