I will be transferring between two international flights at Tokyo Narita airport. I'm scheduled to depart the same day I arrive. I am planning to stay within the airport during the layover. Does anyone know if I will require a transit visa at Narita?
No visa is required for transiting in Japanese airports if you have immediate flight connections regardless of nationality.
Anyway, there is a Japanese transit visa which is intended for people who have longer layovers before transiting and want to go sightseeing or resting in Japan for few days (up to 15 days).
I am an Indian passport holder working in the US on H1B. I was supposed to fly LAX-Narita-KL-Bangalore on 23rd December 2012 with a 14 hour overnight layover in Narita.
I received a call from the airline 2 days before my scheduled departure, stating that new rules at Narita dictate that travelers absolutely need a transit visa for overnight layovers in Narita, even if the arriving and departing flights are from the same terminal.
Because of the short notice, there was no time to apply for a Japanese transit visa (the Japanese consulate takes 3 working days to issue one). I had to cancel my ticket and book a flight with Cathay, transiting thru' Hong Kong which has no transit visa requirements.
A stopover is typically a stay in one city of 24 hours or more. In your case, you actually have just a connection in Tokyo. Connections can even go across airports in the same metropolitan area, such as between London's Heathrow and Gatwick airports.
Very rarely are visas required for connections in the same airport, since you do not need to clear immigration and customs. One exception is in the USA, where all passengers must clear immigration and customs, so check with your travel agent or local Embassy/Consulate for more information.
From my experience, you will not need a visa for this connection, since you are probably flying Japan Airlines and American Airlines, which are located in the same terminal (T2) at Narita. (Even if you're on Air India, they fly into T2 as well.) You will be required to show your boarding pass for NRT-DFW and clear security upon arrival in Tokyo, but you will not clear immigration and customs.
As MeNoTalk mentioned, if you do have a stopover in Japan, you can get a Japanese Transit Visa.
As the other answers suggest, you do not need a visa to transit at Narita, as stated by Timatic, the database used by airlines:
Visa required, except for holders of onward tickets transiting on the same calendar day.
Important to note, however, is that a transit visa is also not required for an overnight transfer (even though Narita's transit area closes at night) even for those normally needing a visa to enter Japan. Rather, by presenting your passport and onward ticket to immigration, you get a 72-hour entry stamp known as a Shore Pass.
Holders of onward tickets transiting to a third country can obtain a Shore Pass on arrival for a max. stay of 72 hours only if there are no connecting flights on the same calendar day