Japan Travel Fixes
Is it true that drugs legal at home can still be illegal in Japan?
Yes. Cannabis is illegal to possess or use in Japan even where it's legal at home, and tourists have been arrested and deported for it. Some prescription medications — certain ADHD medications and strong painkillers among them — are also restricted or banned depending on their active ingredient.
"It was legal where I'm from" or "I have a prescription" doesn't automatically exempt you under Japanese law.
If something is found at customs, you can be detained on the spot — your flight schedule is not taken into consideration.
If you take medication that might be restricted, check Japan Customs' guidance on importing medicine before you travel to confirm.