Short-tailed shearwaters are a migratory species known to have high rates of plastic ingestion, with a 2010 study at Phillip Island, Australia, finding 100% of the fledglings assessed contained plastic in their gastrointestinal tracts. This research sought to monitor plastic ingestion by comparing beachcast fledglings at the same colony after 8 years. No significant differences in overall plastic loads were found, with 98% of individuals containing plastic (n = 52), equating to a mean of 6 particles (107.3 mg) of ingested plastic per bird. Significant changes in the types of plastic being ingested were found, with a higher proportion of user and other plastics compared to industrial pellets, which has also been observed in northern hemisphere studies. Plastics were predominantly user plastic, light in colour, fragmented in shape, and buoyant. The mean diameter of ingested particles was 4.59 mm, with particles over 10 mm being uncommon. Despite the high incidence of plastic ingestion, the majority of birds appeared to have good visceral fat stores, with 92.3% of individuals in the upper half of the condition score scale. Using Fourier-transform infrared spectroscopy, the majority of plastic was identified as polyethylene followed by polypropylene which is largely reflective of world demand, although some plastic types were found in lower proportions than expected.