NOAA Ship McArthur II was acquired from the U.S. Navy in 2002 and was converted by NOAA from a T-AGOS surveillance vessel to a multiple-disciplinary platform capable of a broad range of missions. Like its predecessor, McArthur, McArthur II was named after William Pope McArthur. The vessel was homeported at NOAA's Marine Operations Center-Pacific, in Newport, Oregon.

The ship conducted oceanographic research and assessments, throughout the eastern Pacific, including the U.S. West Coast, Central and South America. McArthur II was involved in studies in several of the National Marine Sanctuaries on the west coast of the United States. The 224-foot ship engaged in measurements of chemical, meteorological, and biological sampling for several large scale programs within NOAA.