Accepted everywhere. The only issue is that you might get stuck with a lot of loose change.
When you travel by bus, its best to have exact change. Just drop the money into the box at the front of the bus when you get on (if you don’t, you can expect the driver to yell at you!)
When you travel by subway, you can purchase a one way or round trip fare in cash from any of the vending machines (English option available) in the station. After you feed your ticket to the turnstile make sure to pick it up and don’t lose it because you’ll need to again to exit at your destination.
Most methods of transportation (City Buses, Metro, Taxi) can be paid for with a T-MONEY card. We recommend that anyone who visits for more than a few days invest in one. The card (or item–they also come in keychain or cellphone charm forms) will cost about W3000 and can be purchased from vending machines in any subway station or in many convenience stores. Once you purchase a card, you can load money onto it and use it for most forms of public transportation. It’s cheaper than paying by cash, especially if you have to transfer, because most transfers are free with the card. It’s also easier than waiting in line to pay specific fares everywhere you go. Just tap the card when you enter the subway or bus, and again when you leave, and it will deduct the appropriate amount. For information on the T-Money Card, visit