Exchanging currency

First off, many places/stores in Japan don't take credit cards so make sure to exchange your cash into Japanese yen.

Withdrawing cash from an ATM is probably the easiest choice. JP Post ATMs and many convenience store ATMs accept VISA bank cards, though 7-Eleven ATMS are probably the easiest. But not all ATMs are online 24/7, so get cash out during the daytime. Also, you may be limited to around 20,000 - 50,000 yen per transaction.

There are exchange services like Travelex and Daikokuya that have multiple branches across Tokyo (including the airport), though their commission is high. Main banks like SMBC, MUFG and Mizuho also offer currency exchange services, but they are only open from 9am to 3pm on weekdays.