When restaurant manager Sam Park, 31, splits bills with friends, he simply "tosses" them the money using a money-transfer mobile app.
Naver Pay is his preferred mobile payment system for online shopping and a credit card for everything else.
"I don't use a lot of cash these days, maybe only when I go to a traditional market," he told The Sunday Times.
"A friend told me about Toss last year. It's an easy way to send money, and I just used it last week to split a restaurant bill with four friends."
Cash is no longer king in South Korea, as more people switch to using credit cards, digital wallets and mobile apps to make payments and, sometimes, just swiping their mobile phones - think Samsung Pay, which is pre-installed on newer models of Samsung smartphones.
Only about 20 per cent of all payments in South Korea are made with cash - among the lowest in the world - according to the Bank of Korea, which is pushing for Asia's fourth largest economy to go cashless by 2020.
South Korea's financial technology (fintech) industry is also blooming after the government's move to ease financial regulations early in 2015 prompted Internet giants like Naver and Kakao to invest more in mobile payment systems that have become widely popular.
Naver Pay has more than 16 million subscribers, while Kakao Pay has 14 million.
Both are expanding their offering of online financial services, with Kakao announcing last month that it secured US$200 million (S$280 million) in funding from a subsidiary of China's e-commerce giant Alibaba.
Toss - similar to America's Venmo - is also a huge success. The app, which simplifies the tedious process of sending money online from 5 passwords and 37 clicks to 1 password and 3 clicks, has been downloaded more than 6 million times and has handled more than US$3 billion in transactions since its launch in 2015.
In a sign of better things to come, the app's developer Viva Republica announced on March 8 that is has received US$48 million in funding from its American counterpart PayPal and other firms.