Weekendvrij allows you to travel free in the weekends up to and back from the Dutch border. For Belgium or Germany you have to pay the normal price.

Tot use your discount you need tot buy an international ticket from where you start in the Netherlands to the city abroad. When you want to travel from Amsterdam to Brussels, you order a card with 100 percent reduction in the Netherlands, so it is free, but you have to pay for the Belgian part from the Dutch/Belgian border up to Brussels v.v. The Dutch NS International is the best option for 100 percent reduction. You will only have reduction when your Weekendvrij is valid.

You always need an ID of passport. When you have purchased the ticket you can open a gate with the square code. No check in, as there is no checkout in Brussels, but you do need to take Weekendvrij with you as a proof that you bought a card with 100 percent reduction in the Netherlands.

Weekendvrij does not include trains in Belgium or Germany, also no direct trains for the part abroad e.g. to Brussels, Berlin of Frankfurt. But the construction with 100 percent reduction in the Netherlands applies. It makes a huge difference.

You can access your international ticket in the app of NSInternational or print it out. Do both for the peace of mind.