Peace activist Margaretta D'Arcy presented herself for arrest at Mill Street Garda Station in Galway today, after refusing to sign a bond pledging not to enter parts of Shannon Airport.
The 80-year-old served a three-month jail term for a similar offence earlier this year.
Accompanied by members of the Galway Anti-War Alliance, she spoke briefly to reporters outside the station.
Wearing an orange boiler suit, D'Arcy said she was not frightened of going to jail.
She said she had already seen the "dysfunction" in the prison system and she said this was mirrored in the way the country was being run.
A short time after she entered the station, D'Arcy was taken away from the building in a patrol car.
Her supporters understand she is being taken to Limerick Prison to serve her sentence.
D'Arcy has said she will refuse food while in custody "in a gesture of solidarity with all those who have lost their lives, their communities and homes destroyed."
When asked if such a decision was wise, considering her ongoing treatment for cancer, she said "If you have cancer the best thing you can do to remove cancer is not to eat."
D'Arcy and Niall Farrell were given a two week suspended sentence on 24 June at Ennis District Court, on condition that they enter a bond to stay away from restricted areas of the airport.
Unlike D'Arcy, Farrell did not present himself for arrest at Mill Street Garda Station in Galway this morning.
His daughter, recently elected Galway City Councillor Mairead Farrell said she did not know where her father was, but that he will not be signing the bond.
Speaking from Berlin, Niall Farrell said he does not know if gardaí called to his home in Oranmore this morning.
He said he intends to present himself to gardaí "when he returns to Ireland from his holidays at the end of July."