Three pupils from Ceredigion contesting the withdrawal of their free transport to a secondary school in another county have won right to a judicial review.
The judicial review is seen as a test case on parental choice
An appeal hearing at the High Court in London has decided that a review into the children's case should go ahead.
The hearing is seen as a test case for parents around Wales who want their children to have the right to travel to the nearest school that provides Welsh language education - even if it is in another county.
The children were originally being taken eight miles from the Cardigan area to a Welsh-medium school at Crymych in Preseli by bus and paid for by Pembrokeshire Council.
But the authority then questioned why it was taking children from Ceredigion without payment and stopped the service.
Ceredigion Council then agreed to pay for some of the 15 children travelling from its area to Preseli but refused free transport for the three pupils from the Cardigan area, one aged 11 and two 12-year-olds.
Two of the children even have older brothers and sisters who are being given the free transport to the Preseli school.
Cardiff-based solicitors, Russell Jones and Walker are representing the children.
"At the hearing the judge accepted that there were important points of legal principle to sort out so gave the children leave for judicial review," said the company's education specialist solicitor Michael Imperato.
"This issue is about children being allowed Welsh-medium education at the nearest available school even if it is across a county border.
The judicial review will take place later this year
Although some of the children live within a mile of Cardigan Secondary School, Mr Imperato said this was not an issue.
"Ceredigion's own transport policy states that if a suitable school is more than three miles away from their home, even if it is in another county, it has to pay for pupils' transport.
"The children want to go to a Welsh medium school and the next nearest one is at Dyffryn Teifi in Llandysul which is 18 miles away," said Dr Dyfed James, the father of one of the children involved in the issue.
The pupils would have to travel 18 miles to Llandysul to get free transport
"If Ceredigion Council get away with not having to provide transport to the nearest appropriate school it could open the door for other local authorities to do the same.
"The council won't even let us offer to pay for our children to go to Ysgol y Preseli so they have a lot of questions to answer.
"I would also like to know how much the taxpayer is having to pay for a top barrister to defend them on this matter."
A Ceredigion Council spokesman confirmed that Nigel Griffin QC was representing the local authority.
She added: "This is a complex issue and it is normal procedure for the authority to engage external legal advice and assistance to ensure proper process are adhered to in accordance with legislation.
"The authority does not divulge contract details with third parties."