Increases are planned for the amount of children's Welsh-language television.
Fireman Sam first aired on the BBC and S4C in 1984
S4C, Wales' fourth channel, will show more than six hours a day for nursery-age children on its digital channel and its website.
The service which could mean more programmes like Fireman Sam, which started out in Welsh, will later be extended for older children.
Pupils in Wales learn Welsh up to age 16 and the number of young speakers is rising.
Currently the channel screens programmes for nursery children - including a Welsh version of Bob the Builder - for around one hour a day.
From June, however, Welsh programmes for pre-school children will be shown every weekday morning from 0700 GMT until 1330 GMT on S4C's digital channel.
The Welsh fourth channel was 25 years old in 2007
After digital switchover S4C, which last year celebrated its 25th anniversary, is due to become a stand-alone Welsh-language channel with no programmes being rebroadcast from Channel 4, as is the case at present.
John Walter Jones, chairman of the S4C authority, said the move was a first step towards a children's branded channel.
He said: "At the end of the day there will be a channel... a specific children service, that is exceptionally important."
He added the broadcaster had budgeted for the new programmes and they were not at "the expense of other services."
Mr Jones said he was "very proud" S4C was the second largest spender in the UK on original children's programmes.
He said the announcement returned to the logic of establishing the channel to provide viewers - nursery children to start off with now - with what they needed, which was good programmes in their own language.
He said: "If they don't get it then they'll move towards the English [language] channels.
"This is a way of investing in the future, to nurture the children in the language and hope to keep them as viewers of S4C."
But some politicians in Wales believe S4C should show some programmes in English to appeal to those who do not speak Welsh.
In May last year, the S4C authority published a consultation paper called Children in the Digital Future seeking the views of the public and stakeholders on its proposals to launch a new Welsh-language public service TV channel for children.