The south west coast was initially surveyed by Dutchman, Pieter Nuytz on the vessel 't Gulden Zeeparedt 'The Golden Seahorse' commanded by Captain Francois Thijssen as part of a landmark expedition of the Dutch East India Company during 1626–27, which mapped the southern coast of Australia. The 't Gulden Zeeparedt reached the south west tip of Australia, near Cape Leeuwin on 26th January, 1627 and continued to sail eastwards mapping more than 1,500 kilometres of Australia's south coast.

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It wasn’t until 164 years later, in 1791 that Captain George Vancouver on board the HMS Discovery, accompanied by the armed tender Chatham sailed past two islands naming them Michaelmas and Breaksea Island as well as other landform including King George the Third’s Sound and Princess Royal Harbour, after the reigning monarch and Princess Charlotte Augusta Matilda, the first daughter and fourth child of King George III.

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The next Europeans to visit the sound were Captain Dennis of the Kingston and Captain Dixson of the Elligood in 1800. A captains logbook kept by Captain Dennis, details a secret two year voyage carried out by the two small ships, owned by the London merchant and whaling  ship owner, Daniel Bennett. The Kingston and the Elligood, were sent to New Holland for whaling, with instructions to examine King George the Third's Sound.  The whalers while in the sound detailed catching three whales and Dixson left an inscribed piece of copper plate behind.

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Following Vancouver's description of a sheltered cove, water source and woodlands and at the urging of the naturalist Sir Joseph Banks, the Admiralty decided to launch an expedition to map the Australian coastline, as well as to further study the plant and animal life on the new colony. On 19th January 1801, the Navy appointed Lieutenant Matthew Flinders as commander of the Investigator, previously known as the Xenophonin and arrived to take command on 25th January 1801 for the first circumnavigate of New Holland (Australia). Attached to the expedition was botanist,  Robert Brown, the botanical artist Ferdinand Bauer and the landscape artist William Westall. The HMS Investigator anchored in the sound from 8th December 1801 to 5th January 1802 and explored the area. Flinders men found the copper plate Dixson had left and during this time and Robert Brown, Botanist and Peter Good, gardener assistant to Botanist collected over 500 samples of plant species.

 

Louis de Freycinet, a Sub Lieutenant of the French navy entered King George's Sound on 11th February 1803 with the schooner Casuarina and the naval corvette Geographe.  De Freycinet mentions in his diary the following words, “the only well-known point of New Holland where it is possible to obtain fresh water at all times.” The crew stayed until 1st March 1803, coming ashore to examine the soil which they found to be sandy. In 1811, de Freycinet published the first detailed map of the coastline of Australia.

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In January 1818, on board the cutter Mermaid, the then Lieutenant (later Rear Admiral) Philip Parker King, son of the third Governor of New South Wales, Philip Gidley King, anchored off Oyster Harbour and came ashore.  King noted that there was smoke near to their landing spot, but did not have any encounters with the local Menang people, however King returned on another voyage on 23rd December 1821, with the schooner Bathurst and dropped anchor on the western side of King George's Sound and one mile from the entrance of Princess Royal Harbour and stayed for two weeks, enjoying cordial relations with the Menang people. 

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Just prior to the arrival of the brig Amity, a French vessel, the Astrolabe had anchored in King George's Sound in October 1826, staying for 18 days. Its commander, Jules Sébastien César Dumont d'Urville, a French explorer and hydrographer, botanist, geologist, astronomer and entomologist who could also speak seven languages, undertook significant biological studies   The renowned French painter, Louis Auguste de Sainson had accompanied the expedition and painted various specimens including portraits of the custodians, the Menang people. These portraits are exceptionally well detailed of the local Menang inhabitants who were pleased to welcome the French visitors to their shores.​

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Due to the presence of French survey ships in the sea around the Colony of New South Wales and the French's avid interest in the west, it was feared that the western half of New Holland was about to be annexed by the French Government.  Concerned by this activity, the Colonial Secretary dispatched a decree, motivating the British Government to expand the British settlement to all shores of the continent. 

 

The British had to act immediately or lose the strategic portion of the continent to another nation, especially their historical arch enemy, France. If this part of the continent was lost to the French, then trade routes from Asia would be substantially effected. There would be no port available for British vessels to shelter and take in provisions.  The trade route between Britain and Port Jackson was paramount and the founding of a penal outpost at King George's Sound would enhance matters greatly. Sailing ships were subject to treacherous weather and the geographical location and the excellence of the harbour, that was detailed by previous explorers, together with the optimistic expectation of finding good country in the interior, induced the government of New South Wales to form a settlement at King George's Sounds.