Children's television programmes will be broadcast on BBC One for the last time on Friday.
Shows including Blue Peter and Horrible Histories will now only go out on the CBBC digital channel.
The Cbeebies strand on BBC Two in the mornings will finish on 4 January, with pre-school programming then only available on the Cbeebies channel.
The changes are part of BBC-wide cost cutting but investment in children's programming will remain the same.
The final strand of CBBC on BBC One will go out on Friday afternoon, featuring a Blue Peter Christmas special and the CBeebies panto.
The decision to end children's programming on terrestrial channels was agreed by the BBC Trust in March, as the BBC looked ahead to the digital switchover.
All analogue transmitters have now been switched off, which means all television broadcasts are digital, and viewers should be able to receive Freeview channels such as CBBC and Cbeebies.
And because of the way young audiences now consume television, there is unlikely to be a drop in viewing figures.
"Children's programmes are absolutely fundamental to the BBC and that is why we have protected investment in them in the light of cuts elsewhere," said the BBC Trust.
"Only a very small percentage of children still solely watch these programmes on BBC One and BBC Two alone, so moving them to digital channels is merely following current viewing patterns and reflects the fact that CBeebies and CBBC will be universally available on digital TV."