Public transportation:
1) Tram 19 from Jernbanetorget (in front of Oslo S) or tram 13 from Dronningens gate towards Ljabru, get off at Kastellet tram-station (appr 450 meters walk).
You can also enter trams in Bjørvika stop and both trams will stop at this stop. Note that there is work on the tram line and you need to go on the bus in Oslo Hospital stop and change to tram again in Ekebergparken stop. Please catch a tram around 13:45 to be there in time.

2) T-bane number 1 or 4 from Oslo S, get off at Lambertseter (appr. 1,5 km walk)
 
After getting off Tram, cross the tram-line and start to walk to the left on Ekebergveien (towards the city center). Walk 2-300 meters until you the Kastellet fire station, and walk into Birger Oliversvei to the right just after the fire-station. You find a red house just across from the main entrance of Kastellet Skole.

It is also possible to go by T-bane to Lambertseter station and walk 1,5 km down Lambertseterveien.

Drivers:
As usual not advisable, but if you must:
Drive from the city center up to Holtet (close to Ekeberg), continue Ekebergveien for approx. 1 km and turn to the left into Birger Olivers vei.

A to A run. We will heat the sauna after run/circle, bring sauna towel and flip flops. :-)