As per SI No 189/1963 Article 22, every cycle, at all times while used in a public place needs to be quqiped with front and rear lamps.
— RSA Ireland (@RSAIreland) March 4, 2019
After all, they are the Road Safety Authority.
Not so fast..
Dublin Cycling Campaign writes:
Article 22 applies to mechanically propelled cycles (more commonly known as motorbikes). Article 29 applies to pedal cycles (bicycles). All of this information is freely available online.
Thanks Conor Kearney