Japan is one of those places where people panic-buy the wrong data plan. Most travellers do not need unlimited data unless they are smashing video uploads, hotspotting, or using maps all day with zero Wi-Fi. For most people, a mid-range plan is plenty. The trick is buying before you fly, installing early, and having your QR code ready. That is the difference between starting your trip smart and standing in arrivals looking confused with everyone else.