The short clip shows the popular Australian naturalist in a small dinghy on the Great Barrier Reef close to the spot where he died in September 2006.
Irwin, 44, who was famed for his daring stunts with dangerous animals, was stabbed hundreds of times by an eight foot-wide stingray as he made a documentary.
This latest video was captured by a British tourist called Steffan Hill, 30, from London.
Mr Hill said: ‘I spoke to him very briefly about what he was doing and told him I really admired and enjoyed his work.
‘It has been almost eight years since the accident and I finally have emotional distance from it.
‘I had nightmares for some time afterwards because I kept thinking we were so close and something could have happened to us.’
Irwin was killed the next day when filming in chest-high water and approaching the animal from behind.
Agencies/Canadajournal