The illegal wildlife trade is covert by nature, and thus is often challenging to study. Seizure data is traditionally the most common means to gain insight into the trade for many species. Online media-sourced seizure records were applied to study the illegal trade of Siamese rosewood (Dalbergia cochinchinensis), one of 33 timber species of hongmu (rosewood), which is logged to produce luxury products predominantly for Chinese markets. Despite recent international pressure to strengthen the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulations, illegal trade of Siamese rosewood is prevalent in its range states. This paper will explore seizure reports in Thai online media and analyse spatial, temporal and other factors that potentially explain the trade. Between January 2014 and April 2016, 835 independent seizures were reported in 37 of 76 provinces in Thailand. Seizures occurred mostly in the north-eastern and eastern provinces with higher numbers of seizures closer to the border. The number of seizure reports decreased over time, and the average number of logs seized per seizure was consistent over the 28-month study period. Inadequate domestic legislation is a key factor facilitating the trade. Improvements are needed to the legislation and enforcement ahead of implementing other regional timber-specific initiatives and regulations. In this specific context, CITES also appears to be unacknowledged and ineffective in hampering the Siamese rosewood trade. Importantly, we find that using media-sourced seizure data is highly apt in Thailand's context, considering Thailand's sensitive political state and the prevalence of trade in other non CITES-listed rosewood species. The approach demonstrated here is applicable to many other wildlife species.