Last year some 64 people stopped working as paramedics in Scotland, according to new data, and unions have warned there is nothing in place to stop staff burnout.
Overall 258 staff left or changed jobs at the SAS in 2021, a Freedom of Information request revealed, including 51 technicians, 48 drivers, and 52 in the control centre.
The service said the numbers did not necessarily represent the number of staff which had quit the service, and may include staff who had held a position to move into another job in the service like a member of the control centre moving from their position following a successful application to a frontline vacancy.
Karen Leonard, GMB Scotland organiser, said: "The numbers are not surprising, but they are a conservative analysis of a crisis, because the true picture for frontline staff is far more critical.
"What Covid-19 has done is expose the impact of real-terms cuts to budgets and resources over the last decade, but while the pandemic will be fuelling staff flight, it's not the root cause of it and there's no getting away from that," she said.
"After years of extreme pressure, and nearly two years of working in a state of fear, staff are angry and exhausted, they have nothing left to give.
"Unfortunately, there is no quick fix to a crisis that's been years in the making.
"Like the entire health and social care sector, SAS needs serious and sustained investment so it can operate efficiently and safely, for patients and staff alike.
"A good place to start a recovery is for the government and management to work with our members properly to address the service challenges, rather than spinning plates in the hope of keeping an emergency service on life support."
The Scottish Ambulance Service said in November it would be "accelerating" recruitment of staff to boost capacity amid current pressures on the system.
A total of 356 front line paramedics, technicians and ambulance care assistants will join the service by March.
Last month it was revealed staffing shortages left the emergency service without the required number of workers for more than one in 10 shifts during the summer months.
The new data, which runs up to November 26, showed that in 2020 some 231 people left or changed jobs in the service, including 56 paramedics.
In 2019, 244 people left or changed jobs, in 2018 there was 205, including 46 paramedics, and in 2017 there was 220, including 49 paramedics.
A spokesman for the Unite union said that there "is nothing in place to prevent burnout despite the SAS being made aware in various forums.
"In November, Unite released the survey findings of hundreds of SAS staff.
"The survey revealed that by huge majorities SAS workers feel under-valued, fatigued, and that staff morale has collapsed, alongside the vast majority of workers stating the nation's ambulance service is under-resourced and under-staffed," the spokesman said.
"Substantial majorities of SAS workers also state that they have considered leaving the ambulance service and reported that they have been abused at work in the last year."
The Scottish Ambulance Service has been contacted for comment.