Solidarity - People Before Profit says they would introduce free public transport for all if they get into government.
The party has launched its green policy, promising to spend €7.1 billion a year on environmental policies.
They say they would add 500 electric buses to the public transport fleet every year until 2030 to make it "frequent and free".
Solidarity People Before Profit is calling for free public transport for all as part of its climate manifesto. Says it’s shocking the Green Party only supports free transport for some #GE2020 pic.twitter.com/zQnGmcZ8NO
— Seán Defoe (@SeanDefoe) January 29, 2020
Elsewhere, they're proposing a pollution tax on airline corporations, an investment in cycle lanes and electrifying the rail network.
In agriculture, they're putting forward proposals including reducing the dairy herd by 50% while compensating farmers with a "New Green Payment".
Elsewhere, the party says they would close all coal and peat-fired power stations while retraining staff on full pay.
They're also pledging the introduction of a state building company to undertake a major retrofitting of the country's housing stock, as well as grants of an average of €30,000 to cover retrofitting private homes.
TD Ruth Coppinger said free public transport would be a key part of their climate measures.
Speaking in Dublin today, she said: "We've put forward the demand - we think we're the only grouping in the Dáil [to do so] - for free public transport as an immediate measure to tackle climate change and to help people get out of their cars.
"[We're proposing] free public transport for all, by the way - not just for students, which the Green Party is putting forward."
You can read the full 'Planet Before Profit' manifesto on the People Before Profit website.