There currently is one option to travel by night train from Wels to Amsterdam, taking between approximately 12 and 13 hours: Namely the NJ 40490 operated by ÖBB.
The Austrian Federal Railways (ÖBB) operate the Nightjet and Euronight trains (the latter together with other national railway agencies). ÖBB night trains typically feature three types of carriages: seats, couchettes, and sleepers. Seats are for the bravest, while couchettes and sleepers provide a more comfortable journey. Couchettes accommodate up to six people, while sleepers are private compartments for one to three people. They may include a private bathroom or shower, or sometimes just a sink.
For the next 7 dates with connections, the cheapest offer starts at 45 EUR. Check our connection pages below for all availabilities!