They were discovered after the Stena Line ferry from Cherbourg to Rosslare docked on Thursday afternoon.
The four adults, two teenagers and two children are all safe and well.
It is understood they were in what is known as a "curtain container" which had come from the French port.
Three ambulances attended the scene and all eight were medically assessed and brought to hospital for check-ups but none of them needed further treatment.
It is understood there was one family of six and two other adults and most, if not all, said they were Kurdish refugees.
They have been brought to Dublin where their claims for asylum will be processed.
Earlier this year, authorities at Rosslare Europort discovered 14 people hidden in the back of a lorry, which also arrived from France.
All 14 people, including one juvenile, were found inside a refrigerated trailer unit.
They did not need medical intervention either.

To protect your email, social networking accounts and the rest of your online life, strong passwords are essential.
But setting and remembering it can be as easy as singing your favourite song.
Here's our step-by-step guide to how lyrics can help you stay safe online.
We'll pick the Foo Fighters, because they're generally great. But it could be anyone you like, or U2. As long as you can remember some of the lyrics to one of their songs.
The catchier the better, to make sure you can remember those words. Something from Nothing seems like a good track to go for, fresh from the Foo's new album Sonic Highways.
It could be the chorus or the bit you like the most. We've gone for the opening lines: "Give me the flammable life, I'm cold as a match." Sing it, Dave.
Take the first letter of each word to make the basis of your password. That gives us GMTFLICAAM. Not bad, but it could someone who knows your music taste possibly guess it?
Mix lower and upper case letters to make the password a little harder to guess. You should end up with something like: GmTFLICaam
Swapping letters for numbers and symbols can make your password even more difficult to guess. So, a capital G looks a bit like 6, we'll swap F for 4 because four begins with f, L and I both look like 1s so that's an easy swap. The @ signs are a good alternative to the letter a. It probably goes without saying, but ours is just an example and not one you should use. Stay safe!
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Eight people have been found in a container which arrived on a ferry into Rosslare Europort in County Wexford in the Republic of Ireland.
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If you needed a reminder that strong passwords are important online, the Russian website  showing thousands of live video feeds could be it.