In Ireland, "Happy Birthday" is sung in English as well as in Irish. The Irish version is called "A Óige agus a Dhia." This song is sung in service on an individual's birthday. The person whose birthday it is will stand in the center of the room, and the rest of the people will join hands in a circle around them. As the song is sung, the circle will move around the person in the center.
I don't know much about the topic, but from what I can gather, "Happy Birthday" is sung in Irish at birthday parties or other celebration events. I'm not sure if there are any specific services that offer this, but it seems like a fun way to add a bit of culture to a birthday celebration.
The Irish government has announced that a new happy birthday song will be played in all Irish public services from now on. The move has been welcomed by many as a way to celebrate the country's rich cultural heritage.