Given the complex and often opaque nature of seafood supply chains, port cities can serve as checkpoints within supply chains to address illegal, unreported, and unregulated (IUU) seafood commodities. Harmonized systems (HS) codes are used at port cities by customs officials to monitor commerce. Concern about IUU activity in capture fisheries has focused attention on the role of HS codes in identifying data discrepancies between trading nations. Only 9.9% of the HS codes, however, are resolved at the “species” level, complicating efforts to deter illegal trade and improving product traceability. To illustrate the useful role of species level HS codes, we evaluated the trading patterns of South African abalone (Haliotis middae) listed and delisted to/from Appendix III of CITES in 2007 and 2010, respectively. Trade data from the International Trade Commission (ITC) was used to analyze trading patterns of H. middae between Hong Kong (HK) and sub-Saharan African nations. Trade data analysis from 2002 to 2015 revealed 1) increased volume of product received in HK, 2) increased dried product over frozen or fresh, and 3) increased trade volume from outside South African borders. In comparison to stable patterns prior to 2007 during an era of higher enforcement, post 2007 trends are suggestive of IUU activity of H. middae and the need for greater scrutiny to prevent illegal trading. This study illustrates that improved HS codes can strengthen Trade Data Analysis (TDA) for identifying IUU products and improve traceability and transparency of seafood traded from developing to developed countries.