Seoul Transportation Cards for Tourists

I'll look into how foreign travelers can use public transport.
I'm looking this up for the first time too, so you should cross-check it.

'# iPhone Apple Wallet T-money

Open the Wallet app and tap the + button on the top right.
Then select Transit Card.
From the country list, choose South Korea → Tmoney.

On the next screen, tap Continue.
Set the top-up amount (choose from ₩10,000 / ₩30,000 / ₩50,000 or enter it yourself) and then tap Add, and you're done.
​
It's not too hard up to this point, and South Korea is at the top of the country list, so it's easy to find.

• References
  • iphone-transit-card-how-to-use-tmoney-with-apple-pay
  • getting-around-korea-after-you-arrive-the-only-transit-card-guide-you-need

'# If you have foreign currency cash or want to make regular payments, WOWPASS

• It has T-money functionality, so you can handle currency exchange and a transit card all at once.
• WowPass balance and T-money balance are managed separately, so definitely keep that in mind. (You might wonder, 'Why can't I ride the subway even though I have money on the card?')
• You can top up your T-money balance through the WowPass app.
• References
  • https://www.wowpass.io/en/guide

'# If you have Korean Won cash, a physical T-money card (inconvenient)

• Just buy the card at a convenience store and top it up with cash, and you're done!

It'll be easy once you try it.
I hope you have a good day today~