A transit officer is attacked at a metropolitan train or bus station every three days on average, according to figures obtained through Freedom of Information laws.
Public Transport Authority records show there were 121 attacks in 2013-14, mostly at night.
They ranged from officers being punched and kicked, being spat at and bitten or sprayed with glass and struck with rocks.
Eighteen attacks were in the city, eight at Joondalup train station and seven at Burswood station.
Six attacks were recorded on the Midland train and two each on Joondalup and Fremantle trains.
PTA spokesman David Hynes said it was unfortunate a small section of the travelling public considered it OK to abuse and assault staff.
"They are wrong," he said.
"It is never OK and we do everything we can to look after our people. We know our transit officers do a difficult and sometimes dangerous job.
"Like police, our transit officers know what they are signing up for - in the interests of our passengers' safety, it is their job to intercede when they identify potential trouble and, hopefully, defuse the situation."
Glynn Moore, a transit guard since 2007, was the victim of an attack last year that left him with a badly broken leg and off work for nine months.
He and his partner were called to Wellington Street bus station where a group of intoxicated men had been refused entry on a bus.
After a series of incidents, one of the men punched a security officer, prompting Mr Moore and his partner to grapple the man to the ground and handcuff him.
Another man came up and pushed Mr Moore in the chest, forcing him to fall backwards with his leg trapped under the handcuffed man.
"I knew my leg was broken straight away," Mr Moore said. "I heard the crack and the pain was immediate."
Despite transit guards being considered as public officers under WA law, Mr Moore's attacker escaped a jail sentence and was fined $2000.
Mr Moore said the behaviour of Perth commuters had definitely deteriorated in recent years.
But he said the 250 PTA transit guards employed in the metropolitan area were well-equipped and well-trained to deal with most situations.
My Hynes said the PTA's state-of-the-art CCTV system meant altercations between staff and potentially violent or abusive members of the public were usually monitored and filmed.
Back-up could be sent where necessary.
"The excellent quality of our vision means we have an extremely high conviction rate when it comes to assaults on our system," Mr Hynes said.
"Put simply, if you offend, we will catch you."