Charging customers to use toilets at bus stations has been branded 'outrageous' after it was revealed transport chiefs raked in more than £340, 000 in the last three years.
Sheffield Interchange made the most from commuters of all the area's bus stations by raising more than £99, 000 since 2014.
Rotherham and Barnsley both made over £90, 000 each – while Doncaster Interchange – which did not introduce the charges until 2015 – raised about £50, 000.
Transport chiefs said the 20p charge has been introduced gradually at all major bus stations in South Yorkshire over the last several years to offset budget constraints, improve cleanliness and to help prevent vandalism and graffiti.
But the South Yorkshire Freedom Riders Group, which campaigns for cheaper public transport for the elderly and disabled, raised concerns about the principle of charging commuters to spend a penny and called for the coin barriers to be removed.
The group's secretary, George Arthur, aged 67, of Barnsley, said: "We understand budget pressures but there are certain things that should be left alone and be free.
"The use of toilets is one of them. They should look at other ways to make money. It is outrageous really.
He added: "The elderly in particular need to have easy access to toilets. But also in this day and age many people don't carry change, they just have their cards to pay for things but the toilets don't have this facility.
"So there are potentially a lot of people who will find themselves in a difficult situation when needing the toilets."
Liz Weber, a vocal ant-cuts protester who launched an online campaign against controversial bus timetable changes last year, added that the toilets are not always available when you really need them.
The 52-year-old, of Grimesthorpe, said: "They say it is to improve services but they are locked down and not available after a certain time. I'm sure when they were free you could access them more often."
The figures were revealed through a Freedom of Information request to South Yorkshire Passenger Transport Executive.
SYPTE said the charges were introduced at Rotherham in 2011, Sheffield and Barnsley in 2012 and Doncaster in 2015, to “help reduce the impact on SYPTE’s funds at a time of increasing budget pressures.”
A spokesman added that the charges are “comparable with facilities at staffed transport facilities elsewhere."
He added: "Any income generated is reinvested to ensure the toilet and other interchange facilities are maintained to the high standard our customers expect.”
He added there are currently no plans to remove the charges at any of the sites.