The Hawaii Undersea Research Laboratory (HURL) was established by the National Oceanic and Atmospheric Administration (NOAA) and the University of Hawaii. Its mission is to study deep water marine processes in the Pacific Ocean. The primary means of surveying are through use of the Submersibles Pisces IV and V and with a remotely operated vehicle (ROV). This dataset contains CTD data from a Seabird SEACAT instrument mounted on the submersibles and the ROV from 593 dives. Sound velocity profiles have been calculated for select dives. There were 17 dives at the Cross Seamount in March-May 1995. The rest were during 2001-2012 in locations from New Zealand to American Samoa in the south Pacific, and from the Line Islands to the Northwest Hawaiian Islands in the north Pacific. The data have not been rigorously quality controlled. Use the data with discretion. Please inform the HURL data management team if questionable signals are encountered. HURL and NOAA are not responsible for misuse of the data. Additional HURL CTD data during 1990-1999 are available in NCEI Accession 0000807.