No discount or coupon codes that I know of but the easiest way to save on Norway In A Nutshell is to actually just book it all yourself because the entire Norway In A Nutshell tour runs on public transit.
By booking it yourself you should be able to save 25-50% off the normal price.
I did it before and it was super easy and saved us quite a bit.
I actually wrote a free step by step guide on how to book Norway In A Nutshell on your own, so check that out.
Did you know the entire Norway In A Nutshell Tour operates on public transit? You can book it yourself and save money with our free step by step guide.