By Train from Budapest (Hungary) to Hamburg (Germany)

Online bookings open: 3 months ahead of the travel date 

When making an online booking, check that you’re looking at booking info for this direct train,

On the DB Bahn booking site look for the journey that has:

0 in the Chg. column

EC (and only EC) in the Products column

and departs Budapest at around 07:41.

Our step-by-step guide to booking train tickets (and reservations) on the DB (German national railways) website is available HERE.
 

RESERVATIONS:

Seats will actually be assigned when booking tickets online on MAV and if you book 1st class tickets on DB.

Book 2nd class tickets on DB, or if you have a rail pass, reservations are optional for this journey, but this train tends to be particularly busy in 2nd class between Praha and Berlin.

So if you want peace of mind that you will have an assigned seat for the entire journey, adding a reservation when making a booking is recommended.
However, if you book in person at the international rail desk at Nyugati station, you will have to request that a reservation be added to the booking.

Rail pass users can purchase reservations online on DB Bahn - or in person at the international travel desks at Nyugati  or Keleti stations - but do that when you first arrive in Budapest, the office is unlikely to be open before the train makes it early start!