Fish and tadpoles, aquatic invertebrates, and baby waterbirds.
When prey is in range the Oblong turtle can strike its head forward to seize it.
Males become sexually mature at a carpace length of 14 cm. Females with a carpace of 15 - 21 cms are usually mature. Nest sites are usually open and free from thick vegetation, and once the maximum daily air temperature remains above 17.5°C the females come ashore to nest. Nesting in Spring is triggered by a falling trend in barometric pressure below 1015Hpa. Females can lay up to three clutches during the nesting season from September to January. Each clutch ranges from 3 -15 eggs The natural incubation period ranges from 183 to 222 days, depending on weather conditions. Hatchlings are approximately 31 mm in carapace length.