Kensington Palace said Thursday it is "anticipated" the young Prince George will accompany his parents, but that a final decision will be made "in due course."
The palace said the trip will take place in April 2014 and that William and Kate - known as the Duke and Duchess of Cambridge - were invited by the New Zealand and Australian governments.
It said further details on the exact dates and itinerary will come "in due course."
The Duchess of Cambridge hasn't visited either country. William last visited New Zealand and Australia in March 2011, shortly after an earthquake hit Christchurch and floods hit areas of Queensland and Victoria.