This dataset contains high-performance liquid chromatography (HPLC) pigment data (19But, 19Hex, Allo, β Car, α Car, Chl a, Chl b, Chlc 1,2, Chl c 3, Cphlid, Diadino, Diato, Fuco, Lut, Neo, Peri, Prasino, Viola, Zea) from the U.S. GEOTRACES GP15 Pacific Meridional Transect from Alaska (56°M) to Tahiti (20°S) along 152°W between September 24, 2018 and November 24, 2018. Samples for pigment analysis were collected at 6 depths at every major station (N=23 stations) and filtered onto GF/F filters, which were frozen at -80°C until analysis at the HPLC Facility at Oregon State University managed by Ricardo Letelier (https://ceoas.oregonstate.edu/ocean-ecology-and-biogeochemistry-facilities). Samples were extracted and analyzed on a Waters 996 absorbance photodiode array detector in combination with a Waters 2475 fluorescence detector in September 2019. These data were collected by the GP15 management team to provide biological context for the geochemical measurements made by GEOTRACES PIs. This dataset contains the data from Leg 1 of the cruise (RR1814), from Seattle, Washington, USA to Hilo, Hawaii, USA. Leg 2 data are provided in a separate dataset (see 'Related Datasets' section of metadata).