The three boys and a girl - all aged 10-14 - were discovered safe in the New South Wales town of Grafton on Sunday.
They had left Gracemere, in Queensland, sometime earlier in the weekend. One boy reportedly wrote a note to his family to say he was leaving.
Police said they would lay charges, but did not specify which ones.
The children were not all from the same family and had stolen the 4x4 from one of their parents, authorities said.
'Barely reaches window'
