The group started a two-week quarantine on arrival on January 14 in the central Chinese city where the first known cluster of virus cases emerged in 2019.
Wearing masks, they peered at the ranks of waiting media from the window of a bus which whisked them from the quarantine hotel, although it was not immediately clear when and where their investigation will start.
The virus is believed to have come from bats and to have initially spread from a wet market in Wuhan where wild animals were sold as food.
The WHO insists the visit will be tightly tethered to the science of how the virus which has killed more than two million people and laid waste to the global economy jumped from animals to humans.
In a mission dogged by delays and obfuscation from their Chinese hosts, it was not clear what the expert team will be allowed to see in Wuhan or what useful evidence remains a year after the outbreak in a country which has vigorously controlled the narrative of how the pandemic began.
The early days of the outbreak remain among the most sensitive topics in China today, with the Communist leadership seeking to stamp out any discussion that shows its governance in a poor light.
Beijing has also sought to seed doubt into the origin story, floating the unsubstantiated theory that the virus emerged elsewhere.
Another theory, amplified by former US President Donald Trump, is that it leaked from a laboratory in Wuhan where researchers were studying coronaviruses.
A panel of independent experts concluded this month that China and the WHO could have acted more quickly to avert catastrophe during the early stages of the coronavirus outbreak.