Most manure stored in grazing dairy farms is wastewater collected from the milking parlor and adjacencies. Anaerobic lagoons are designed to treat this liquid waste by reducing solids and oxygen demand, but may release methane, ammonia, odors, and pathogens in the process. Treatment intensification may be a more efficient and economical long-term solution for small grazing dairies. LSU AgCenter Dairy Waste and Nutrient Management Team have been evaluating technologies and practices to improve wastewater treatment using the Southeast Research Station Dairy Wastewater Treatment Evaluation System (DWTES). The system is a replicated set of anaerobic lagoon, aerobic lagoon and constructed wetlands. The objective of this study was to evaluate the effect of artificial floating islands on DWTES effluent quality. Biohaven Floating Islands (Martin Ecosystems, Baton Rouge, LA) were deployed in an anaerobic lagoon (186-m² floating islands) and an aerobic lagoon (93 m² floating islands). Wastewater was sampled from every stage, approximately every 3 mo for 17 mo. Samples were analyzed for temperature, pH, chlorophyll-A, chemical oxygen demand (COD), total solids, total dissolved solids, total suspended solids (TSS), ammonia-N, nitrate-N, nitrite-N, total Kjeldahl nitrogen (TKN), total phosphorus, anions, dissolved oxygen concentrations, total coliforms and E. coli. Total solids (931 mg/L), COD (711 mg/L), TKN (72 mg/L) and sulfate (14 mg/L) concentrations in raw wastewater decreased by 50% or more in the system’s effluent. Escherichia coli counts were reduced from 6.5 log MPN/100 mL in raw wastewater to 3 ± 0.41 log MPN/100 mL in wetland effluents. Floating islands improved treatment effluent for TSS (66 vs. 49 ± 18 mg/L), COD (212 vs. 168 ± 16 mg/L), and TKN (27 vs. 21 ± 2 mg/L). Ammonia-N as a proportion of TKN and nitrate-N (3.79 vs. 4.73 ± 1.1 mg/L) increased in the replicate containing floating islands. Floating islands appeared to effectively improve dairy parlor wastewater treatment in a multi-stage treatment system.