Quantifying dissolved organic carbon (DOC) in peatland–aquatic systems is essential for understanding inland carbon fluxes, yet conventional laboratory-based approaches limit spatial coverage in remote field settings. Field-based proxies are therefore often used, with fluorescence-based fDOM sensors representing the most common approach in aquatic systems; however, their applicability in peat porewaters remains poorly constrained. Here, we compare a traditional fDOM field proxy with a novel low-cost colorimetric alternative for estimating DOC under field conditions. To this end, porewater and surface-water samples were collected from three peatland complexes in the Clay Belt of the Canadian Shield, Ontario, during June and August 2025. Sampling depths varied between 0-200 cm and reflected diverse wetland types and water sources. DOC proxies included handheld fDOM measurements on unfiltered samples collected in situ and a Nix portable colorimetric sensor measured on filtered, low-volume samples within 24 hours of collection. These optical measurements were paired with concurrent field measurements of pH, temperature, turbidity and specific conductance, and regressed against laboratory-measured DOC. Across the dataset, fDOM showed no clear relationship with DOC in peat porewaters. In contrast, significant relationships were observed between DOC and colorimetric absorbance. Preliminary results show that combining the 400 nm optical wavelength with pH and specific conductivity explained ~70% of the variance in logDOC concentration (p<0.01), corresponding to a prediction uncertainty of ~30% (−25% / +33%). While not suited for high-precision estimates, this approach is fit-for-purpose for resolving relative DOC gradients and improving spatial and seasonal coverage where logistical challenges constrain sampling density.