There were a few signs in May. Then a dozen last weekend and two on the weekend just gone.
Commuters, boaters and pedestrians have been inspired, angered, even confused by the messaging.
The Mail set out to uncover who put the signs there and what motivated them.
Spending hours buying and painting tarps and then hanging them during the darkest part of night takes, well, a bit of dedication.
It's one thing to do it once for your Grandpa John's 80th birthday to thank him for a couple of decades of lollies, fishing trips, advice and generally being awesome. But it's another to do it to send out messages to strangers, weekend after weekend.
"This is my purpose, we've got to look after our own," says the woman, one of the perpetrators. "We can't save the world but we can do our best to save the people of Mandurah, inspire people and give them hope for the future."
The Greenfields single mum makes and hangs the signs together with a man, a tradie who lives south of Mandurah and works full-time. They are unrelated but started talking a few months ago over some signage he had put on his car. Neither wants to be identified.
Both say they feel "so strongly about what's happening" that they're prepared to sacrifice as much of their time, money and energy as it takes.
The latest two signs put up on Friday night read 'Welcome to the great awakening' and 'Reclaim your freedom'.
"There is this growing number of people questioning everything," the man said. "We don't realise how many people are questioning because so many are afraid to say something. When people do open up they realise how many people are aligned with their views."
Some of their other messages include: 'Coercion is not consent', 'Question everything', 'Just a mask, just a lockdown, just your freedom', 'COVID is only a distraction', 'Resist the great reset' and 'Breathe'.
'Breathe' is her favourite message, says the woman, and the intent behind it is two-fold.
"Health isn't found behind a mask or in a needle, we are supposed to be breathing fresh air," she said. "Also just chill, relax because fear and stress is causing a lot more problems than COVID."
The man said people were "so quick to throw their rights away for fear" or because they had been told to do so.
"Some people are getting vaccinated so they can get on a plane - but it's not a promise that if you get vaccinated you can fly," he said. "We should be able to trust our government, our media, unfortunately they're compromised," he said. "Whoever is paying you the most money is the one that controls things.
"I think we've all forgotten that we've never trusted the government, politicians give us false promises."
The idea to put up signs was to reach a lot of people at once and they thought it more effective than attending a rally in Perth.
"How do you get your message out to people these days - you could do a flyer drop but that's a whole lot of wasted paper," the woman said. "You can jump on social media and it gets deleted, it's only that algorithm of people that are seeing it."
AMA calls for ad campaign targeting vaccine hesitancy
Meanwhile, the Australian Medical Association (WA) has called for an advertising campaign "specifically targeting vaccination hesitancy and misinformation".
President Andrew Miller said this was vital if WA had any hope of reaching herd immunity and both the state and federal governments had been "missing in action" when it came to providing a compelling argument for vaccination.
Governments estimate that between 60 and 90 per cent of people would need to be fully vaccinated to achieve herd immunity.
But 15 weeks into the national vaccine rollout less than 20 per cent of Australians have received their first dose.
There is hesitancy among over 50s unwilling to receive AstraZeneca and outright anti-vaxxer sentiment is growing.
The WA state government's Roll up for WA campaign began in April and was allocated $1.5 million. It features frontline workers explaining their reasons for getting vaccinated.
The next phase of the campaign is expected to be released in coming weeks.
Meanwhile, the Federal Government is preparing to launch a new campaign in July which will cost the majority of its $40 million budget dedicated to COVID-19 advertising.
That push is timed to coincide with a ramp up in vaccine supply.