The couple has already visited Nottingham and the multi-ethnic Brixton district of London but Wales is especially important given that Markle's fiance is Prince Harry of Wales and the second son of Prince Charles the Prince of Wales.
One of these lucky recipients included Moortown, U.K. resident Edna Levi, who said she was so "thrilled" with the engagement news that she personally wrote the couple a note of congratulations.
They didn't disappoint, taking plenty of time to chat to those gathered outside to meet them and shaking hands, apologising profusely for being late.
The Royal Love Story will begin at the moment Prince Harry and Meghan Markle met, and continue all the way through their dealing with the media and the intense attention surrounding their lives together.
Prince Harry and Meghan Markle are to visit Cardiff to celebrate the people, culture and heritage of Wales. A visit to Scotland and possibly even Northern Ireland might be expected before the wedding. There they learned about how sport is being used to engage young people and how it aids social development.
The objective of their visit was to celebrate Welsh culture and tradition - and where better to do that than at Cardiff Castle, which is 2,000 years old. They also met notable sports men and women and got a chance to see how local organisations are promoting Welsh culture and language.
The visit included a stop at Cardiff Castle. They were greeted by a sea of Welsh flags with a few American ones through the crowd too.
Ms Markle was carrying a £295 DeMellier Mini Venice handbag in green Forest Grain colour, and was wearing Tabitha Simmons Kiki boots.
Harry wore a long naval force coat over a lighter blue sweater and clerical and naval force trousers. Some eagle-eyed Royal watchers think they've figured out the sex of Kate Middleton's baby, thanks to her outfit choices. "They were so cute honestly", an eyewitness shared.