But already all eyes are on three-year-old George aged two-year-old Charlotte, who are expected to attend only one or two of the royal engagements.
For their parents, the visit to Poland and then to Germany will inevitably be viewed in the context of Brexit.
William and Kate's trip to Germany and Poland is being taken at the request of the United Kingdom Foreign and Commonwealth Office.
On their first official visit to Poland they have come with their children, Prince George, who will be 4 on Saturday, and Princess Charlotte, 2. The couple, along with other members of the royal family, have visited a number of European countries in recent months in what is being called a "Brexit royal charm offensive" as the United Kingdom negotiates its withdrawal from the European Union.
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After arriving at Warsaw's airport, they were driven in a motorcade to meet President Andrzej Duda and First Lady Agata Kornhauser-Duda at the Presidential Palace for lunch.
They will visit the Warsaw Rising Museum, dedicated to the 1944 Polish uprising to liberate Warsaw from German occupation during World War Two.
In Germany, Chancellor Angela Merkel will hold a private meeting with the royal couple in Berlin before they visit the Brandenburg Gate, a symbol of German unification.
During their five-day tour William and Kate will also meet survivors of the Holocaust and Nazi oppression as well as visiting the former Stutthof concentration camp and Berlin's Holocaust museum and memorial.
Perhaps the penultimate event of the royal tour will be when William and Kate take their competitive streak to the water as they captain crew boats in Heidelberg.