In fact, the first international relations out of Australia, so the first time Australians dealt with those overseas, was not conducted by descendants of the the British settlers post 1788. It was peaceful trade conducted as early as the 16th or 17th centuries between Indigenous Australians in Arnhem Land and Makassans from Sulawesi in now Indonesia, well before Captain Cook had laid eyes on the country. Products traded by indigenous Australians ended up being sold in China, so Australia's tradition of selling stuff to the big country up north has been going on far longer than people realise.
The first 'Englishman' (recorded) to have encountered Australian Aborigines would have been William Dampier, North West Australian coast, in January 1688, a full 100 years before the first fleet and 80 years prior to Cook.
He has the dubious account of creating a stereotype of them that persisted until even today from the book that was produced from his journals, and most likely helped attribute 'terra nullius' in conjunction with Cooks accounts. He rounded up several of the locals in an attempt to make them work carrying their water back to the ship. Called them a 'miserable lot' when they had no clue what he asked of them so did not comply, and writes with indignation "So we were forced to carry our own water back to our ship..." That shame of not being able to force the locals into slave labor for the day, how rude of them. He also made sketches of the event that have been found in his journals.
In any case this all happened not far from an island named after Dirk Harthog (Dutch), who had visited the area in 1616. The aborigines that Dampier encountered did have evidence of having traded with other Europeans, such as the Dutch, and has more accounts from the journal of his HMS Roebuck expedition that explored the north end more thoroughly from 1699. Dampiers books and journals are a good read, he definitely was before the age of political correctness, so expect some interesting commentary. Dampier had a number of times where his crew mutinied or just left him behind on an island, so I assume he was not the most charismatic leader.