| 30th September - On this day in Irish, world and technological history |
| 1816 - A group of estate gardeners met to drink beer at the Rose Tavern, Donnybrook, Dublin and to worry about “the art of gardening falling away and rapidly declining”. This became the inaugural meeting of the Horticultural Society of Ireland (later the Royal Horticultural Society of Ireland). - More info: Royal Horticultural Society of Ireland |  |
| 1889 - The Bundy Manufacturing Co., a maker of time recording equipment, is incorporated. It is the first of many components that eventually became the Computing-Tabulating-Recording Company, Inc. (C-T-R), which will later become IBM. - More info: Bundy Manufacturing Company |  |
| 1955 - Film star James Dean dies in a road accident aged 24 - More info: James Dean |  |
| 1967 - BBC Light Programme, Third Programme and Home Service are replaced with BBC Radio 2, 3 and 4 Respectively, BBC Radio 1 is also launched with Tony Blackburn presenting the first show - More info: BBC |  |
| 1979 - Pope John Paul II addresses 285,000 people at a youth rally in Galway, before travelling to Knock, County Mayo where a further 300,000 people hear him speak. He also visits Clonmacnoise and Galway. - More info: Visit by Pope John Paul II to Ireland |  |
| 1980 - Ethernet specifications are published by Xerox working with Intel and Digital Equipment Corporation. - More info: Ethernet |  |
| 1982 - "Cheers" began an 11-year run on NBC-TV. - More info: Cheers |  |
| 1994 - Taoiseach Albert Reynolds and members of the government wait at Shannon Airport to greet President Boris Yeltsin. He fails to leave the aircraft to meet them. - More info: Boris Yeltsin circling over Shannon diplomatic incident |  |
| 2004 - The leader of the Democratic Unionist Party, Ian Paisley, makes an historic first visit to Dublin for political talks with Taoiseach Bertie Ahern. - More info: Ian Paisley |  |
| 2004 - The Luas "Red Line" commences operation from Tallaght to Connolly Station. - More info: Red Line (Luas) |  |
| 2008 - The Government decides during the night to offer a 400 billion guarantee to initially 6 leading Irish banks to prevent their collapse due to the global Economic crisis - More info: Post-2008 Irish banking crisis |  |
| 2015 - Apple releases OS X El Capitan (version 10.11). OS X El Capitan includes features to improve the security, performance, design and usability of OS X. Apple's typeface San Francisco replaces Helvetica Neue as the system typeface. - More info: OS X El Capitan |  |
| 30th September - Number one in the Irish and/or UK singles charts on this day over the years |
| 1955 | "Rose Marie" by Slim Whitman | (UK chart) |  |
| 1960 | "Tell Laura I Love Her" by Ricky Valance | (UK chart) |  |
| 1966 | "Distant Drums" by Jim Reeves | (UK chart) |  |
| 1971 | "Hey Girl, Don't Bother Me" by The Tams | (Irish chart) |  |
| 1972 | "How Can I Be Sure" by David Cassidy | (UK chart) |  |
| 1978 | "One Day at a Time" by Gloria | (Irish chart) |  |
| 1978 | "Summer Nights" by John Travolta and Olivia Newton-John | (UK chart) |  |
| 1989 | "Ride On Time" by Black Box | (UK chart) |  |
| 1994 | "Saturday Night" by Whigfield | (Irish chart) |  |
| 1995 | "Fairground" by Simply Red | (Irish & UK chart) |  |
| 2000 | "Against All Odds (Take a Look at Me Now)" by Mariah Carey featuring Westlife | (Irish & UK chart) |  |
| 2004 | "Real to Me" by Brian McFadden | (Irish chart) |  |
| 2006 | "I Don't Feel Like Dancin'" by Scissor Sisters | (UK chart) |  |
| 2010 | "Written in the Stars" by Tinie Tempah featuring Eric Turner | (Irish chart) |  |
| 2017 | "Too Good at Goodbyes" by Sam Smith | (UK chart) |  |
| 2021 | "Shivers" by Ed Sheeran | (UK chart) |  |
| 2022 | "Unholy" by Sam Smith and Kim Petras | (Irish chart) |  |
