Start with a clinic, not an article
Book a doctor or travel clinic at least eight weeks before you fly, because only they can weigh your own health, history and itinerary. This page is general travel-health information, not personal medical advice. Eight weeks is the window the UK FCDO gives, and it exists because some courses need more than one dose spread over time. Before you travel, check two things the FCDO puts first: that your destination can provide the healthcare you may need, and that you have appropriate travel insurance for local treatment or unexpected medical evacuation. That matters most if you have a health condition or are pregnant.
Routine vaccines and the risks named for Japan
Start with your routine vaccinations being up to date, then ask the clinic to check the current recommendations for Japan. The FCDO points travellers at the NHS travel vaccinations page for what is advised and what you pay for, which changes over time, so a page like this one should not pretend to hold the list. For health risks in Japan the FCDO names dengue, biting insects and ticks, and pertussis, also called whooping cough. It also notes that altitude sickness is a risk in parts of Japan, which matters if your plans include high mountains. Which of these applies to you is the clinic's call, not this article's.
The medication law that catches people out
Japan strictly enforces a law on anti-stimulant drugs, and it is illegal to carry in some common prescription and over-the-counter medicines. The FCDO names Vicks inhalers, medicines for allergies and sinus problems, cold and flu medication containing pseudoephedrine, and some over-the-counter painkillers containing codeine. Foreign nationals have been detained and deported for these offences, so it is worth the ten minutes. If you travel with medication, check its status with the Japanese embassy in your country before you fly, and read the general guidance on travelling with medicines from a travel health service. Carry what you bring in its original packaging with a copy of the prescription.
Healthcare in Japan, and 119
For an ambulance, dial 119 and ask for one. Medical facilities in Japan are high quality, but treatment is expensive and you should expect to pay the whole cost of anything you receive. Facilities may check your insurance first, which can delay your treatment, so have your policy number and the insurer's emergency line saved offline on your phone. Contact your insurance company quickly if you are referred to a medical facility. The FCDO publishes a list of medical providers in Japan where some staff speak English, which is worth saving before you travel rather than searching for it in a waiting room.
Bites, heat, water and staying reachable
Since the FCDO names dengue and biting insects and ticks, bite prevention is the everyday habit worth keeping. Use repellent, cover up in wooded and grassy areas, and check for ticks after a hike. Summer is the other practical risk: August in Tokyo runs above 31°C with high humidity, so drink water, slow down in the afternoon and treat heat seriously. On tap water the FCDO health page makes no statement, so check locally, and bottled or filtered water is the usual advice when you are unsure. Keep your phone working and charged: it holds your insurance details, your translation app and the weather agency alerts for earthquakes and typhoons.
