Japan is a world leader in cancer treatment. Japanese hospitals must be run as non-profit and must be managed by physicians. There are around 8,300 hospitals in Japan, 650 of them are in Tokyo.

National Health Insurance (国民健康保険, Kokumin-Kenkō-Hoken)
If you’re living in Japan and have National Health Insurance you pay only 30% of the treatment cost.

International patients
As an international patient you pay the full cost of medical treatment. However it’s a fraction of the cost of medical care in many countries. For example, some advanced cancer treatments can cost 10 times more in the USA.

Most hospitals and clinics in Japan don’t deal with international patients directly. You need to contact them via a medical travel assistance company such as:

Emergency Assistance Japan
http://maj.emergency.co.jp/

JMCH (Part of JTB Corp.)
https://j-medical-healthcare.com/en/jmhc/flow/check/

Some hospitals in Japan have special facilities and services for international patients. You can find them using Japan Hospital Search:
http://www.japanhospitalsearch.org/

Medical Tourism is promoted by the Japanese government:
https://medicalexcellencejapan.org/en/

If you’re coming to Japan for treatment you need a medical visa called “Visa for Medical Stay”
https://www.mofa.go.jp/j_info/visit/visa/medical_stay1.html

Paying For Your Medical Treatment in Japan
You pay each time you are treated, at the hospital, after the treatment. For example, if you have a CT scan, a blood test and a consultation with a doctor on the same day you’d pay at the hospital or clinic just before you leave.
If you’re staying in the hospital, you pay on the last day of a hospital stay. Some hospitals ask for a deposit first eg. ¥100,000 ($790) Some may ask for a guarantor. It’s not legally binding.

For advanced treatments like immunotherapy or proton beam therapy you must usually pay for part of the treatment in advance by bank transfer.

In some cases you can pay by credit card. Remember you may need to ask your bank to increase your card limit as the medial fees can be high (eg. $20,000-$40000).

With an international bank transfer all the details must be 100% correct. If even one piece of information is wrong, such as a misspelled name, the transfer is rejected.

Japanese banks use SWIFT/BIC codes but other bank codes eg. IBAN, ABA, Routing Number or Sort Code aren’t used in Japan.

After you’ve made the transfer, the clinic or hospital will check with the bank. If the transfer hasn’t come through there’s nothing they can do except wait and check again. Sending a screen shot or a reference code from your bank is, sadly, of no use to the clinic or hospital.

If a bank transfer doesn’t go through, only the “sending bank” can fix the issue. The Japanese bank can’t do anything except say something like “The details aren’t correct” or “No transfer was made”.

Travelling to Japan for Cancer Treatment

Here are some useful websites for you to plan your trip to Japan:
1. Tokyo Cheapo
https://tokyocheapo.com/
2. Matcha
https://matcha-jp.com/en/list?region=113
3. Best Living Japan
https://bestlivingjapan.com/
4. Bento
https://bento.com/ (Food)
5. Happy Cow (Veg and Vegan food)
https://www.happycow.net/
6. Jorudan (Online train timetable)
https://world.jorudan.co.jp/mln/en/?sub_lang=nosub
7. Tokyo Family Stays (Short-term rentals in central Tokyo)
https://www.tokyofamilystays.com/
Many thanks to Shantha Deshpande for the recommendations!