From Bremen Airport, there is a direct coach service to Oldenburg - Public Express. There are stops in Oldenburg at the Hauptbahnhof, Pferdemarkt and the university.
Alternatively, catch tram 6 from the airport to Bremen Hauptbahnhof, then catch a train.
At the airport, it is also possible to take a taxi to Oldenburg.
There are usually two or three connections per hour from Oldenburg to Bremen operated by Deutsche Bahn and Nordwestbahn (Tickets are valid in the trains of both companies). The fastest train takes 28 minutes, the S-Bahn trains take up to 38 minutes. The fare is around 8€ for a regional trains (NWB and RE) and Intercitys (IC). Please note that IC trains can only be used with a regional ticket between Emden/Norddeich and Bremen. From there on a supplement is necessary for all Intercity trains. The ICE trains always require a supplement. Other regional services are linking Oldenburg with Wilhelmshaven (for the ferry to Helgoland), Emden (ferry to Borkum), Norddeich Mole (ferries to Norderney and Juist), Osnabrück and Leer. The trains are usually running every 60 minutes and every 30 minutes during peak time on some routes. See the Deutsche Bahn online timetable for details.
ICE high-speed trains and IC long distance trains operated by Deutsche Bahn are running via Bremen e.g. to Munich, Leipzig, Dresden and Berlin.
People travelling to or from Groningen have to change trains in Leer, trains between Leer and Groningen are operated by Arriva and run every hour. Make sure to have the right ticket when you cross the border at Nieuweschans. Also don't take any weed with you. The police might be waiting with a dog on the platform in Leer.
You can reach Oldenburg from the A1, A7, A27 and E22 highway.
Oldenburg as located at the river Hunte and the Küstenkanal (coastal canal) There are two yacht clubs having a small harbour.
The central station and the city centre can be easily explored as pedestrian. For longer distances there are Bus services to all parts of the town. The main interchage stations are Lappan and ZOB (central station). Getting around by bike or car is easy. For parking in the city centre you should follwow the signs to one of the several parking garages.
Carl von Ossietzky University (founded 1973) is an important regional university.
There are a host of eateries in the city center, including a variety of doener stands, Chinese Food, a McDonalds and a Burger King for the cash-strapped college student. On weekdays the Pferdemarkt hosts a market at which you can buy fresh baked breads, vegetables, and meats.
There is a good selection of small cozy places in Wallstrasse.