Aluminum alloys are commonly used for engineering applications due to their high strength to weight ratio and low cost. Pitting corrosion, accelerated by saltwater environments, can lead to fatigue cracks and stress corrosion cracking during service. Two-dimensional (2D) characterization methods are typically used to identify and characterize corrosion. These methods, however, are destructive and do not enable an efficient means of quantifying mechanisms of pit initiation and growth. In this study, we have used lab-scale x-ray microtomography to non-destructively observe, quantify, and understand pit growth in three dimensions over a 20-day corrosion period in an AA7075-T6 alloy. Pit depths were quantified over time using renderings of sample volumes, leading to an understanding of how inclusion particles, oxide formation and breakdown, and other corrosion mechanisms impact the growth and morphology of pits.