A relatively small crowd of about 200 is at the botanic gardens, but inclement weather may be keeping many away.
Queensland Premier Annastacia Palaszczuk has urged locals to come and say hello at the walk that starts around 3.15pm NZT.
Charles and Camilla will attend the Games opening ceremony where the Prince will officially open the competition on behalf of his mother, the Queen.
They'll also visit Lady Cilento Children's Hospital before heading to the Gold Coast for the Games' opening.
The tour is the 16th trip to Australia and the seventh to Queensland for Charles, while it is Camilla's third visit.
It comes at an important time for the British monarchy, with republican sentiment gaining traction in Australia.
Prime Minister Malcolm Turnbull, who supports an Australian republic, says he is looking forward to catching up with the prince, who he says is a thoughtful, charming and knowledgeable man.
"We always get on very well," he told ABC Radio. "The prince and I, and Lucy (Turnbull) share a lot of common interests, particularly in terms of urbanism, architecture, planning, environment and ecology."
Charles will also visit Bundaberg and Cairns during his trip to Queensland, and is scheduled to fly to Vanuatu and the Northern Territory before heading home next week.
- AAP
