Nature photographer Greg Tannos says, "what started out as a walk in Royal National Park to get our minds off these disastrous fires, ended up being a pleasant surprise".
"When we stopped to look out over the Hacking River, this beautiful 2.5 metre Diamond Python was at our feet," he said.
Mr Tannos, of Alfords Point, quickly shot a video for his website, findmyaustralia.com
"More than ever now, please look after our wildlife," he said.
The Australian Museum says, "The Diamond Python is found in large bushland areas and national parks of Sydney, but often goes undetected because of its nocturnal, slow-moving habits.
"Like all pythons, the Diamond Python kills its prey by wrapping itself around its victim (in this case, small mammals and lizards) and suffocating it.
"During the day, the Diamond Python may be seen basking in trees and occasionally it is found in roofs and rafters.
"The female Diamond Python lays eggs and coils around them to protect them and keep them warm. This maternal care, which is uncommon in snakes, ceases once the offspring hatch.
"The Diamond Python is not as widespread in Sydney as it once was and, although it is not considered endangered, it is under pressure from habitat destruction.
"Pythons are non-venomous but can inflict a painful bite. Teeth can break off and remain embedded in the victim."