The southern African nation is best known among travellers for the enormous Sossusvlei sand dunes of the Namib Desert, but reports suggest the couple are looking instead at a safari trip to Hoanib Valley Camp in the country's northwest.
Rwanda is also speculated with Markle having visited as a World Vision global ambassador in the past, an experience she described as incredible.
The country offers gorilla sighting experiences, a volcano-rippled landscape and – as a little-visited Central African country – tranquillity.
Botswana, where the couple holidayed in the early days of their relationship, is also a good bet.
Markle's engagement ring features a stone from Botswana with diamonds from Diana's personal collection.
Other possible destinations could include Malawi, Amalfi Coast, Tuscany, Hawaii, Turkey, the Philippines and Nevis in the Caribbean Sea.
Harry holidayed with his mother on Nevis in 1993. In 2016, he returned as part of his Caribbean tour.
Or, could the Prince follow his older brother's lead and book out North Island, the $9800-a-night private island on the Seychelles where William and Kate honeymooned in 2011?
Almost everyone arrives by helicopter to the 11-villa property, all billowing cotton, thatched walls and distressed wood furniture.
Staff outnumber guests by two-to-one and freshly caught seafood and champagne is a daily staple on the menu. Villas boast timber four-poster-beds and plunge pools.
Charles and Diana spent their honeymoon on board the Royal Yacht Britannia in 1981.
The Prince of Wales earned the name Crazy Horse for his overzealousness when it came to deck hockey matches with the crewmen.
Wherever they go, the newlyweds will be looking to get away from the limelight as they start their married life.
