In Australia, they will pet a koala in a Sydney zoo, visit in the drought-stricken Outback town of Dubbo and meet indigenous leaders on Fraser Island, the world's largest sand island, in northeastern Queensland state.
Prince Harry and his wife Meghan are believed to have touched down in Sydney early on a drizzly Sydney morning. It was initially reported the pair arrived on a British Airways flight.
They may also be recovering from the Friday wedding of Harry's cousin Princess Eugenie to Jack Brooksbank.
The couple had no official functions on Monday following a 22-hour flight.
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That would necessitate product standard checks on some goods coming into Northern Ireland from elsewhere in the UK. She added: "This backstop arrangement would not be temporary".
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The Serbian legend, who has won the last two Grand Slams, took the first set 6-3 as he outclassed 21-year-old Coric. Open, is now world number three, but could move up a spot if he books a place in Sunday's final.
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The launch of the Singapore-Newark service signifies a new era of growth for the important United States market, he said. Customers can also experience high-speed in-flight Wi-Fi service on Singapore Airlines' new A350-900ULR aircraft.
Admiralty House has also been used to host other worldwide guests including US Presidents and the Pope.
Having some well deserved rest before a full on couple of weeks, Harry and Meghan will be formally welcomed to Admiralty House by the Governor-General Sir Peter Cosgrove on October 16, taking in views over Sydney Harbour before meeting representatives from the 18 countries involved in the Invictus Games in Sydney.
The tour will conclude with a four-day trip to New Zealand, where they will be greeted by Prime Minister Jacinda Ardern.
The Duke and Duchess of Cambridge - Harry's brother and sister-in-law - came to Australia and New Zealand with a young Prince George in 2014 for an 18-day visit. Although the royal couple have over 80 engagements arranged throughout their special trip, the main event on their itinerary is this year's Invictus Games which will be held in Sydney.
The visit comes six months after Prince Charles made his 16th official visit to Australia, primarily to open the 21st Commonwealth Games on Queensland's Gold Coast.