Individual tickets (single journey and/or round trip) may be cheaper than a rail pass depending on the number of train segments you travel during the period. If you have a definitive schedule you can take advantage of advanced purchase Minipris pricing. Note that you can only book travel up to 3 months in advance.
https://www.nsb.no/en/frontpage
https://www.nsb.no/en/our-tickets/minipris
Minipris is an offer determined by the interaction of demand and
availability. Consequently, price may vary over time and you may find
fewer Minipris tickets on the most popular departures.
Tickets must be purchased at least on day before the date of travel.
This applies to both online, mobile and ticket machine purchases.
Ability to use US signature credit cards has evolved. See: https://www.nsb.no/en/our-tickets/3d-secure
You can quick and easily buy tickets on nsb.no by using the Travel
Planner on the right. You can use Visa, PayPal, Mastercard and Diner
cards. We recommend paying with PayPal for our customers from the
United States, Canada and Australia. Credit cards from these countries
often lack a security protocoll used for safe payments in Europe.
Should you experience problems with any card purchases, please contact
your card issuer / bank. Alternatively, call the NSB Call Centre on
815 00 888/+47 23 62 00 00.