If you arrive in the Netherlands at the Amsterdam International airport Schiphol, the easiest way to travel to Groningen is to take the train. The underground train station is located near Schiphol Plaza, within minutes walking distance from the luggage claim areas. The Dutch railway system is run by Nederlandse Spoorwegen and known as NS. You will readily recognize it by its yellow and blue colors. Just follow the yellow illuminated signs that direct you ‘To the trains’.
It is important that you purchase a train ticket to Groningen before you board the train. Passengers travelling without a valid ticket will be fined. You can buy either a first-class ticket (€ 43.70 one-way) or a second-class ticket (€ 25.70 one-way). There are two ways of purchasing a ticket: at the ticket office where you can purchase a ticket from a railway officer in person, and from the yellow and blue ticket-vending machines that you will find in the luggage claim hall and near the entrance to the train terminal. Note that for paying with credit cards the pin code is required.
The ticket contains a microchip with your destination; do not forget to activate it (aka "check in"; otherwise the ticket is not valid!) at a check-in station near the staircases down to the platform. There are no check-in stations at the platforms at Schiphol so that if you forget to check-in, you will have to go one level up.
Information on travelling by train can be accessed at the NS website. Every hour there is a direct train from Schiphol Airport to Groningen. Additional connections via the train to Leeuwarden (also every hour) involve just one simple change of trains (in Zwolle). The journey from Schiphol Airport takes 2 hours 10 minutes regardless of the particular train. The trains are quite comfortable and feature the free wireless internet at most of them. However, there is no form of refreshment service on the train so be sure to purchase your snack at Schiphol.
The Oosterpoort is located at walking distance from the Groningen Central Station. When exiting the station, go right (do not cross the water!) and keep following the road along the channel. After about 800 meters you will see The Oosterpoort on your right.
There are smaller airports at Eindhoven, Rotterdam and even Groningen. If you fly from inside Europe, it might be a good idea to check them for suitable flights as the prices offered by discounters might be very competitive to large companies operation from Schiphol. All these airports have frequent bus connections to the respective railway stations.
Please note that the entire city centre of Groningen is off limits for cars. There are ten parking garages located near the centre. The ones closest to The Oosterpoort are the Oosterpoort parking or the Rademarkt parking. The parking garage Oosterpoort is located at Trompsingel 23 and is opened Mondays-Saturdays from 7 a.m. till 7 p.m. The parking garage at Rademarkt is located at Rademarkt, 27 and is opened Sundays-Wednesdays from 7 a.m. till 1.30 a.m, on Thursdays from 7 a.m. till midnight, on Fridays and Saturdays it is opened 24 hours.
More information on car parking in Groningen, including the street parking regulations, can be found here.
While driving thought Dutch cities and villages, be aware of the numerous cyclists that may not exactly follow the traffic regulations.
You might find the website http://9292.nl/en very useful for planning your journey in the Netherlands. The planner combines all available public transportation - trains, buses, trams, metro, and boats - to provide an optimal route. It also informs you real-time about the current delays and disruptions in public transportation.
Groningen has various taxi companies, here's a small selection of them.
Taxi Groningen: +31 (0)50 541 8452
Taxi Noord: +31 (0)50 549 4940
Taxi VTG: +31 (0)50 301 5222
Taxi's are also located outside the central train station.
Information about visa can be found in this brochure (from the Dutch immigration and naturalisation service). If you need a visa to enter the Netherlands, please contact the conference organizers for the invitation letter.