These two presentations highlight innovative passive-sampling approaches to improve the monitoring and assessment of per- and polyfluoroalkyl substances (PFAS) at Department of War (DoW) sites. The first presentation titled "Ion-Exchange Membranes as Passive Samplers for Diverse PFAS" presents the development of ion-exchange membranes as cost-effective, equilibrium passive samplers capable of measuring time-averaged PFAS concentrations while accounting for variations in pH, temperature, salinity, and dissolved organic matter without requiring site-specific calibrations. The second presentation titled "Demonstration of a Commercially Available Peeper Passive Sampler for PFAS in Sediment" demonstrates the application and validation of a commercially available dialysis-based passive sampler at two DoW aqueous film-forming foam (AFFF) sites, comparing passive-sampling results with traditional sampling methods and PFAS bioavailability measurements. Together, the presentations demonstrate how passive-sampling technologies can provide more efficient, practical, and potentially lower-cost tools for characterizing PFAS concentrations, sources, and bioavailability in water and sediment, while supporting more informed and sustainable monitoring programs.