In the shadow of the city’s world famous castle, crowds are expected to gather on the esplanade on Tuesday to meet the prince and his fiancee when they greet well-wishers.
Later they will travel to a Social Bite which supports the homeless and has been visited by number of famous faces including Hollywood star George Clooney.
The trip to Scotland will be the fourth public appearance Ms Markle and Harry have made together and follows successful visits to Nottingham, Brixton in south London and Cardiff in the months that followed their engagement announcement in November.
Also on the esplande will be the Royal Marines Band Scotland who will play for Ms Markle, the former Suits actress, and the Prince who became Captain General of the Royal Marines in December 2017.
Kensington Palace had said: “Throughout the day Prince Harry and Ms Markle will have the opportunity to meet members of the public, learn more about organisations that work in the local community and nationwide, and celebrate youth in the Scottish Year of Young People 2018.”
Inside the castle at the historic Edinburgh Garrison, which looks out across the city, the couple will watch as the One o’clock Gun is fired, a tradition started in 1861 to mark time for ships in the Firth of Forth.
The couple will then move on to the New Town to visit Social Bite, a social enterprise cafe which distributes 100,000 items of food and hot drinks to homeless people across Scotland each year, as well as employing staff who have experienced homelessness themselves.
In the cafe, Harry and Ms Markle will learn more about the social enterprise, meet staff and tour the kitchen.
They will be the latest in a string of high-profile visitors to Social Bite premises.
Hollywood star Leonardo DiCaprio stopped for lunch at Social Bite venture Home in Edinburgh’s west end in November 2016 while the Duchess of Cornwall and George Clooney have been to Social Bite’s Rose Street branch.
Prince Harry and Ms Markle will round off their visit by attending a reception at the Palace of Holyroodhouse to celebrate youth achievements marking Scotland’s Year of Young People 2018, an initiative that aims to inspire Scotland through its young people.