Kerry's famous dolphin Fungie may have been spotted by a fishing boat near Dingle harbour last night.
Fungie boat operators say they will carry out a search later this morning.
The bottlenose dolphin has not been seen since Wednesday.
A number of boats have been involved in searches for the dolphin at the mouth of Dingle harbour.
Local boatman Jimmy Flannery said: "We have a report that he was seen following a fishing boat out the mouth of the harbour early on Wednesday morning but he hasn't been seen since," he said.
"It's unusual for him to go missing but I wouldn’t be overly concerned yet. I’d be hoping he’s just gone hiding for a while. But it is unlike him."
Fungie first arrived in Dingle in 1983 and has been an ever-present attraction since.
Up to 12 boats run daily trips to the dolphin during an extended tourist season, with thousands of visitors seeking to catch a glimpse of the friendly dolphin.
Experts say some bottlenose dolphins can have a lifespan of up to 50 years. Fungie is believed to be at least 45-years-old.