RTÉ One is an Irish free-to-air flagship television channel owned and operated by RTÉ. It is the most-popular and most-watched television channel in the country and was launched as Telefís Éireann on 31 December 1961, it was renamed RTÉ in 1966, and it was renamed as RTÉ 1 upon the launch of RTÉ 2 in 1978. It is funded partly by the government's licence fee; the remainder of the funding is provided by commercial advertising. Because RTÉ is funded partly by the licence fee it shows considerably fewer advertisements than most other channels available in Ireland and Northern Ireland.

 

RTÉ One is available to 98% of the Irish population in HD on the Saorview DTT service. It is also available in Northern Ireland via Saorview, Freeview, Sky, and cable provider Virgin Media. The channel is also available online through RTÉ Player.