The file contains measurements and modelling results of iron (Fe) speciation of water samples collected on the Peruvian shelf and slope region. Determinations of iron speciation were analyzed via Adsorptive Cathodic Stripping Voltammetry (Gledhill and Buck. 2012, Frontiers in Microbiology). Modelling results of dissolved iron speciation and the apparent Fe(III) solubility were calculated using the NICA-Donnan model (Kinniburgh et al. 1999, Colloids and Surfaces A) via chemical speciation software ORCHESTRA (Meeussen. 2003, Environ. Sci. Technol.).