We are U.S citizens and will be traveling to Japan from SFO in June, originally to stay 2 weeks. We are just now thinking of adding a week in Seoul, Korea to depart from Haneda or Narita before returning to Japan for our flight back to SFO. Do we require a transit visa for traveling from Japan to Korea?
First of all, if you are a US citizen, don't worry about visas. You are allowed 90 days of visa free travel to both Japan and South Korea, which is absolutely sufficient for you.
If I am understanding you correctly, your travel route is SFO-NRT/HND(TYO)-ICN/GMP(SEL)-NRT/HND-SFO. You will transit via Tokyo from Seoul to San Francisco.
Not all transits through Japan require transit visas. If you are staying airside for the transit, you don't need a transit visa. If you either:
- need a change of airports, e.g. NRT to HND, or vice versa; or,
- need to stay overnight for your transit
then you will need to apply for a transit visa. When you leave Japan for Seoul, you have ended your stay in Japan and thus "used up" your single-visit temporary visitor visa.
So you have two (actually three) options:
- book a SEL-TYO-SFO return flight that doesn't require you to change airports or stay overnight. This is very easy to do, and is probably the best option for you;
- if you are qualified, you can apply for a multiple-entry visa. If you are the citizen of a CIS (ex-USSR) state, Georgia, India, China (PRC passport holder), Indonesia, Philippines, Vietnam, and/or Qatar, you may be qualified as a tourist;
- failing both, apply for a transit visa. Well, why do this.