TDs Mick Wallace and Clare Daly were separately brought to prison for non-payment of a fine - and promptly released.
Ms Daly spent just over an hour in Limerick Prison before she was released at 10.30pm. Mr Wallace spent slightly longer - around three hours - and was put on temporary release just before 4.30pm.
The arrest of both TDs arises from their breach of security at Shannon Airport and their subsequent refusal to pay €2,000 fines.
Mr Wallace was arrested by appointment in Clontarf at 11.30am yesterday, before being driven to the prison by two gardaí. On arrival, he shouted to an assembled crowd: "It probably won't be as bad for me as it is for the people in Syria, Iraq and Afghanistan."
He had earlier spoken in the Dáil on education issues.
Before leaving Dublin, Mr Wallace travelled the short distance to his home and collected a bag of clothes and a number of books.
Despite being handed a 30-day sentence for the non-payment of a €2,000 fine, Mr Wallace was released around three hours later.
Prison sources emphasised that in cases of non-payment of fines, those convicted are often released within a number of hours, depending on the circumstances.
After his release, Mr Wallace claimed that he has no intention of paying the fine, which was issued to both him and Ms Daly for breaching security at Shannon Airport in July 2014.
The pair used a rope to scale the fence in order to inspect US aircraft using the airport to refuel.
Last night, Ms Daly was also arrested in Dublin and taken to the same facility by gardai, arriving at around 9.15pm.
She was also given temporary release just over an hour later.
Speaking after her brief period in jail Deputy Daly remained defiant about the validity of her actions in Shannon Airport last year. "The gas thing is I heard people commenting earlier on, 'do they think that we as law markers should be breaking the law?' she said.
"We think we have a responsibility under the Nuremberg principles when we see an injustice being done."
Deputy Daly said she was given time to say goodbye to her daughter and pack a bag before she was brought to Limerick prison
Speaking outside the jail after his release, Mr Wallace also said he was determined to continue his campaign against the use of Shannon Airport by the US military.
"Don't worry, we will get in there (Shannon Airport) again. It's an absolute disgrace that the planes are not being searched and we will keep at this until the Government cops on."