Peter's Place Café in Waterville has posted a sign reading, "No Bus/Coach tours or loud American's. Thank you."
The pub is on a tourist route in the area known as the Ring of Kerry.
Twitter user Maurice Campbell of Northern Ireland posted a picture of the sign on his account.
It must be a great thing in life to have your money made! Waterville, Co. Kerry pic.twitter.com/jZccZhsMs9— Maurice Campbell (@mauricecampbell) June 6, 2014
"I thought it was out of order. It seemed nasty," Campbell told CNBC.
He went in and attempted to speak to owner Peter Fitzgerald about the sign. "I went in and told him 'I'm a bit loud myself, but I'm not American.'" Campbell said. "He just gave me a look."
Tourism is a big part of the area's economy, so an unwelcoming attitude could be costly.
The Waterville Business Association said "the sign in no way represents the views of Waterville businesses or the community as a whole" and that "Americans are always welcome in the village," according to Radio Kerry.