There is no parking by the Munch Museum during the Øya festival. The festival takes place in the Tøyen park next to the museum from August 7th until August 11th, and parking might be limited until Sunday August 12th.
We recommend using public transport when visiting the Munch Museum during the weekend of the festival. The museum is located a few minutes of walking away from the Tøyen Metro station (T-bane). Bus no. 20 stops right next to the museum, at the 'Munchmuseet' bus stop. There is also an Oslo City Bike stand at Tøyensenteret, close to the Metro station.