When’s the best time to buy the JR Pass

Hi there,

We will be arriving in Japan on 07 Dec for our 9 day trip (Tokyo-Osaka-Kyoto-Nagoya-Tokyo). We’re keen to buy the JR pass as it seems more cost effective than buying individual tickets for our trip.

Can you let us know when’s the best time to purchase the JR Pass? Can we do it now or once we arrive in the airport-Narita (buy online)? And when will the validity start? We plan to buy just the 7 days as the first 3 days, we will mostly stay in Tokyo.

Tokyo - 3 days (arrival)
Osaka - 2 days
Kyoto - 2 days
Nagoya - 1 day
Tokyo - 1 days (departure)

Thanks in advance!