Despite the Netherlands' sensible business attitude, intercity bus transport has still not been liberalised, in order to protect the pampered national railway company. But there are good international links at excellent prices from Groningen to Germany and beyond. All buses depart from the central station.
Groningen is on Eurolines' Amsterdam-Hamburg-Copenhagen-Oslo/Stockholm route, three times per week. Ecolines has buses to Vilnius in Lithuania, while Becker Reisen goes to Gdansk in Poland.
German bus company MeinFernBus (www.meinfernbus.de/en) has three direct daily buses from Groningen to Hamburg (4 hours, from €16) and Berlin (7,5 hours, from €28), including a night bus.
The Public Express bus also drives into Germany, connecting Groningen to Oldenburg and Bremen (with a stop at Bremen airport) for €7-23.