In short:

Game and collectibles shop owners are bolstering their security because of a rise in Pokémon card thefts.

One card store owner says almost $20,000 worth of Pokémon and other trading cards were allegedly stolen from his shop.

Another trader says these cards have a high resale value.

When Benjamin Hill went to his collectables store one day, he was shocked to find the ceiling smashed through and almost $20,000 worth of Pokémon and other trading cards gone.

"It was pretty confronting to be honest … I was aware this could happen, but you never think it would be you," the shop owner said.

"I was shaking a little bit as well; it took me a few days to get over it."

Mr Hill said the alleged thief had sneaked through the back toilet door and crawled through the ceiling at his Blair Athol shop in early September.

He said Pokémon trading cards could have been the target, as they generally cost between 50 cents and $50 but some rare cards were being auctioned for millions of dollars.

Mr Hill said these trading cards were high in value, untraceable and easy to resell.

"It's just a little bit of cardboard that can fit in your pocket. You could have $1,000 in your pocket," he said.

SA Police told ABC News a 47-year-old man was this week arrested and charged with serious criminal trespassing, theft and property damage over the alleged break-in at Mr Hill's store.

Mr Hill said he had since upgraded his security and taken all expensive items off site.

Thefts on the rise

In recent months, tens of thousands of dollars' worth of trading cards were stolen from collectables shops in Brisbane, Perth and Melbourne.

SA Police arrested a 29-year-old man who allegedly smashed a glass cabinet at a Noarlunga toy store and stole Pokémon cards last month.

ABC News spoke to several Adelaide shop owners, including one who was spending about $20,000, to bolster security measures such as installing bollards, fog alarms, roller shutters and new CCTV.

Card shop owner Hung Nguyen is one of those taking extra precautions.

"What's happening around Melbourne and Queensland, it's just made us think twice about looking into our security a bit more," he said.

"I guess there's nothing stopping us from comparing ourselves to a jewellery shop."

Lucrative market

The Japanese game is 30 years old but Pokémon trading cards have seen a global resurgence in recent years, prompting its government to consider a clampdown on the industry.

Due to a lack of supply, high demand and influx of investors, Pokémon cards are soaring in price, with an American YouTuber selling an ultra-rare card for a record $22.6 million this year.

Recently, these Japanese cards have been outperforming Bitcoin and the S&P 500 on the stock market.

"Like a box that was worth $100 to $200 is now worth $8,000," Mr Nguyen said.

The trader said most of these cards were being resold for more than double their retail price.

"You could say the return on investment is 100 per cent, which is crazy," Mr Nguyen said.

"So for them, it's, 'Why wouldn't I get into it and make a quick flip?'"