Originally Posted by
abmj-jr
To be crystal clear, if you activate the 14-day Rail Pass on Sunday and use it the same day, it will expire at 11:59.59 pm on Saturday 2 weeks later. If your flight out is on Sunday, you would need to pay for the ride back out to the airport. You could also activate the Pass immediately on arrival but designate the next day (Monday) as the "start date,' but then you would need to pay for the first train into the city on arrival day. Pretty much the same out-of-pocket expense.
However, neither the N'EX nor the Limousine Bus will break your budget (they're both about ¥3000 plus change), so if there's a long line at the JR Center at NRT, just pay for the N'EX, the bus, or the Skyliner (even cheaper, especially if you're staying in Ueno or another northern part of the Yamanote Line) at the ticket counter in the Arrivals Lobby and don't worry about the cost.
The reverse also works. If your Pass runs out the day before you leave, simply go to Tokyo Station (or whichever station you are closer to) and buy a ticket there. It should be fine as long as you are not leaving during a major travel period. Give yourself plenty of time so that if the ffirst train you try is sold out (unlikely), you can try the next one.