This record describes data from the Condensation Particle Counter (CPC) collected on the Marine National Facility RV Investigator Event voyage IN2015_E01. This was a cold-water trial voyage for the RV Investigator departing Hobart on the 29th January and returning to Hobart on the 18th of February, 2015. The Condensation Particle Counter (CPC) TSI 3772 measures the concentration of the total number of particles greater than 10 nm in diameter.