The family were pictured arriving at the airport in Warsaw, with George wearing a smart blue shirt and shorts, and Charlotte sporting an adorable patterned pink dress.
William opted for a classic suit for the occasion, whilst Kate went brave for a woman travelling with two small children, in a stunning white jacket and skirt.
At the beginning of July, Kensington Palace confirmed that George, almost four, and Charlotte, two, would join their parents, the Duke and Duchess of Cambridge, on the tour of Germany and Poland.
A spokesperson for the family said: 'The Duke and Duchess are very much looking forward to this tour and are delighted with the exciting and varied programme that has been put together for it.'
'They have decided that their children, Prince George and Princess Charlotte, will travel with them and we expect the children to be seen on at least a couple of occasions over the course of the week.'
'They look forward to a busy and impactful tour, and are grateful that they will have the opportunity to meet the Polish and German people - such important friends of the United Kingdom - as a family.'
It's not the first time the young royals have attended official trips with their mum and dad - in September 2016, both children went on a visit to Canada, where they made appearances arriving and departing at respective airports, as well as at a children's party in British Columbia.
Prince George also flew to Australia and New Zealand for their extensive trip in 2014 (who could forget the adorable snap of him at Taronga Zoo, meeting his namesake bilby?)
On their latest adventure, the family will travel across Poland and then head to Germany, concluding their trip in Hamburg, Germany on July 21st.
It's thought that on this occasion, the children will only be seen during arrivals and departures at the two countries, although their parents are scheduled to visit a number of important landmarks, and meet with leaders including Angela Merkel.
They'll also participate in a head-to-head race which will see William take on Kate in rival boats on behalf of twinned towns Cambridge and Heidelberg.