There has been a 6% fall in the number of people who watched S4C on TV each week in Wales in the last year, the channel has said.For at least three minutes a week during 2014/15, 360,000 people watched compared to 383,000 the year before. Chairman of the S4C Authority Huw Jones said viewing figures in the annual report should be "handled with care". He said public service channels BBC Two and Channel 4 had also seen falls of between 5-7%.
There was a 10% increase in the number of people across the UK who saw the Welsh language channel for at least three minutes a week - from 551,000 in 2013/14 to 605,000 - during 2014/15.
There was also an increase of 31% in the number of online viewers to the channel, with 5.7 million viewing sessions via its website and apps.
Meanwhile, the BBC Trust, in a statement within S4C's annual report, warned "the channel's ability" to reach and engage its core Welsh speaking audience was "in flux".
It cited the rising appeal of its online and UK-wide services, and the drop in its core TV audience in Wales.
S4C receives the majority of its annual funding, around £75m, from the BBC licence fee, with a further £7m from the UK government.
'Welsh exiles'The channel is about to enter detailed discussions on its future funding with the UK Culture Secretary John Whittingdale and the BBC Trust.
Mr Jones said an increase in the number of repeats shown by S4C was "a matter of concern" for the governing body.
Meanwhile, he warned "care must be taken that this does not lead to a service lacking in freshness, particularly in peak viewing hours".
More viewers watched S4C's live online and catch-up services during 2014/15, while those watching on their mobile phones increased by more than 230% to almost 3 million.
Mr Jones said S4C needed to take advantage of the latest technology to serve its audiences.
He said the channel's increased reach beyond Wales meant that "numerous Welsh exiles are using contemporary technology increasingly to enable them and their children to continue to be part of the everyday life of Wales through the medium of Welsh, wherever they live".
Chief executive Ian Jones said the introduction of all of S4C's programmes to the BBC iPlayer last year, alongside the continuation of its Clic online platform, had seen increased numbers of viewers to both services.
Viewing via S4C Online and iPlayer increased across both services on Clic/S4C Online from 261,000 in March 2014 to 274,000 by the end of March 2015.
They also rose from 11,000 to 474,000 on iPlayer during the same period.
"This is very positive news and also an indication of how the audience use and view content in new ways," said Mr Jones.
Source: S4C, 2014/15 aggregated