Imidacloprid is an insecticide used in Great Barrier Reef (GBR) catchments to control the threat of pest species (particularly the grey-backed cane grub, Dermolepida albohirtum) in agricultural areas. Its high potency to insects and low toxicity to mammals has increased its popularity, resulting in increased application and environmental detections. Run-off and other environmental losses from treated agricultural land have led to imidacloprid entering the surrounding aquatic environments, contributing to poor water quality, and posing a toxic risk to a range of freshwater and marine organisms, habitats, and ecosystems. The catchment area includes agricultural land used for sugarcane and banana production, which are known to contribute to pesticide run-off and contamination of waterways. The Great Barrier Reef Catchment Loads Monitoring Program (GBRCLMP) has monitored for imidacloprid since 2009. In this study, we used trend analysis to determine if the concentrations of imidacloprid at 14 sites that discharge to the GBR have changed between 2009 to 2022. A previous study conducted between 2009 and 2017 found that various sites had imidacloprid concentrations above ANZ ecosystem protection guideline values to protect 99% and 95% of species. In the current study only 13 of the 14 sites had imidacloprid detections. Change Point and Seasonal Mann-Kendall analysis showed there were five sites where there was no change in imidacloprid concentrations, three sites where the concentrations were stable and then significantly decreased, three sites where concentrations initially significantly increased and then plateaued off, and two sites where concentration initially significantly increased and then significantly decreased. While exceedances of the guideline values still occur, the risk since 2017 has generally decreased and this indicates that pesticide management strategies are having a positive effect on water quality, at least for imidacloprid.