Japan has no International Health Regulations certificate requirement for UK travellers, so this is usually not about proving vaccination at the border. It is about checking sensible protection before you go. Routine UK vaccines should be up to date, including MMR and diphtheria, tetanus and polio. Tetanus is commonly relevant because it follows cuts, puncture wounds and contaminated soil exposure, and a booster may be advised if medical facilities could be harder to reach or your last dose was over ten years ago. Japanese encephalitis is the vaccine people most often have not considered. The infection is spread by mosquitoes that bite mainly from dusk to dawn, with higher relevance around rural areas, rice fields, marshland and pig farming. In Japan, JE is reported countrywide apart from Hokkaido, where animal cases have been reported. Short visits limited to major cities are usually lower risk, but longer rural stays or uncertain itineraries deserve a proper discussion. Dengue risk is also reported in Japan. The mosquitoes that spread it bite during the day and can be found around towns and cities. Vaccination is not a routine choice for most first-time travellers, so bite avoidance carries most of the weight. Tick-borne encephalitis is another Japan-specific consideration for outdoor travellers, with reported risk in parts of Hokkaido, Honshu and Kyushu. Hepatitis B vaccination may be considered for longer stays, new sexual partners, contact sports, medical work, tattoos, piercings or possible healthcare abroad. Rabies is not reported in Japan, but bat lyssavirus is a low-probability risk after bat contact.