This dataset was collected on the R/V Kilo Moana, which departed and returned to Honolulu, HI, with most of the cruise spent following an anticyclonic eddy northeast of the Hawaiian islands. Two biooptical instruments were plumbed to the underway uncontaminated seawater (intake depth 6m). Data for each instrument were averaged to the minute and matched to a timestamp on the minute. C-STAR: Filtered values (<0.2 um) removed from all data (see White et al., 2017, GRL); ECO: filtered values (<0.2 um) removed from chl and volume scattering data; chl fluorescence converted to mg/m3 using factory calibrations. CDOM not included due to faulty channel. Time is in UTC.