Until after the Second World War Radio Éireann was only able to afford to broadcast in the evenings with the exception of a programme of records in the afternoon.

RTÉ Radio 1 has been carried on shortwave in DRM during specific events, including the All Ireland finals.

During the station's overnight downtime, Radio 1 simulcasts the output of the digital "classic hits" channel RTÉ Gold.

AM transmissions continued on longwave 252 kHz from Summerhill, County Meath until 14 April 2023, aimed to serve Irish people living in Britain and used the old Atlantic 252 transmitter.

In 2007 a new telefunken tram 300 kW transmitter was installed which is capable of DRM (Digital Radio Mondiale) broadcasts which can transmit up to seven services in near FM quality, but consumer receivers are not being manufactured.

Most complaints about the closure of mediumwave were from groups such as fishermen and the elderly,[11] also from people who did not have the longwave band on their radios.

It differed in certain respects from that broadcast on FM, particularly at the weekend, with significant additional sports coverage and religious programming.

This reduction in power meant that interference from the French-language station Alger Chaîne 3 – broadcasting on the same frequency from Tipaza with a daytime power of 1,500 kW and 750 kW at night – was considerable, and particularly affected reception of RTÉ Radio 1 on longwave on the south coast of Ireland after dark.

[14] However, RTÉ subsequently announced that it had postponed the closure until 19 January 2015 "in order to ensure that listeners, particularly in the UK, have sufficient time to understand and avail themselves of alternatives".

[15] As a result of further public pressure, especially from elderly Irish listeners in Britain, churches, the GAA, emigrant groups, and listeners in Northern Ireland who wouldn't all have access to RTÉ on FM or DAB, it was announced in December 2014 that the 252 frequency would be kept on the air until at least 2017,[16] and in March 2017 that transmission on longwave would continue until June 2019.

[19] The final long wave broadcast occurred during the Late Date music programme of Friday night into Saturday morning, 14/15 April 2023, presented by Ciara King.

The unused 248m long wave transmission mast at Clarkstown near Summerhill, County Meath was demolished on 27 July 2023.