Accurate and reliable monitoring of amphibians is essential for informing their management and conservation. Pseudophryne semimarmorata (Southern toadlet) is a species of endangered brood frog with a largely terrestrial life history and has experienced a widespread decline across the Melbourne region. This study sought to identify whether environmental DNA (eDNA) could be used as a non-invasive method to detect and monitor the Southern toadlet during the breeding season alongside traditional call surveys. We collected 73 water samples for species-specific analysis from 35 sites (water bodies) throughout the breeding season, concentrated in areas with historical records of Southern toadlets. We also employed predictive models to reveal the environmental parameters associated with the presence of calling males. eDNA had limited in-field success to accurately detect the species, with positive detections recorded on three occasions, all taken from the same site. In contrast, call surveys detected toadlets on 41 of the 73 occasions where water was concurrently sampled for eDNA. We identified a greater presence of calling males at higher water temperatures which was, in turn, more likely at the onset of the breeding season (early Autumn). While eDNA sampling is a promising tool to monitor many amphibians and other aquatic taxa, our results demonstrate that it may have a limited ability to detect Southern toadlets in their environment. A largely terrestrial life history, small population density, and small biomass of individuals likely all contribute to the low eDNA detection rate of Southern toadlets. These insights will help inform decisions surrounding the appropriateness of using eDNA as a survey method and highlight the valuable role of pilot studies before widespread implementation.