More than 2,000 posters are being displayed around the country as part of a new anti-racism campaign.
The initiative is being run by the Immigrant Council of Ireland, in association with the National Transport Authority and transport providers.
It is aimed at raising awareness of racism and urging people to report racist incidents.
Last year, a similar campaign in Dublin saw 217 reports, an increase of 51%.
CEO of the Immigrant Council Brian Killoran said: "The question this campaign encourages people to ask is whether the person sitting opposite you should be treated any differently to you because of the colour of their skin, or their nationality."