This dataset includes Partial pressure (or fugacity) of carbon dioxide, water temperature, salinity and other variables collected from surface underway observations during NOAA Ship Oceanographer, NOAA Ship Discoverer, and R/V Akademik Korolyov cruises in the Pacific and Indian Oceans from 1986-05-21 to 1989-04-20. These cruises were conducted under support from the National Oceanic and Atmospheric Administration (NOAA). Carbon dioxide measurements in the atmosphere and in surface water were made by analyzing of mixing ratios of CO2 with an automated, temperature-controlled gas chromatographic system described by Murphy et al. (1991) and Bates et al. (1993). Instrument precision was determined by the average percent standard deviation of the standard response over a 6-hour period. The precision varied between cruises but was always less than 1.2% and was more typically around 0.4%. Air was pumped through 3/8-inch diameter, plastic-coated, aluminum tubing from the jackstaff on the bow of the ship (10 meters above the sea surface) to the oceanographic laboratory for analysis. Surface seawater entered the ship via a forward intake line located approximately 5 meters below the water level.