Originally Posted by
KQ321
I haven't checked whether the NS ticket machines sell the IC Direct supplements.
I believe you can. Just did a little digging on the NS International site and found
this:
Please note: There is also a surcharge for the Intercity direct. You can also buy the supplement ticket at the self-service ticket machines at the stations.
And as a reminder:
Non-residents of the Netherlands
The self-service ticket machines only accepts Dutch debit cards or chipknip (an electronic cash system in the Netherlands). For non-residents of the Netherlands it is therefore only possible to pay using euro coins.