I seem to have a problem booking anything in Norway for the end of May beginning of June. All the hotels seem to be booked, and the Norway in a nutshell website has conflicting information. I have never had these types of problems in any country I have visited . Does anyone have any suggestions. I did contact the TI but to no avail.
Have you tried Thorn Hotels. Looks like Thorn has rooms available in Oslo late May-early June but space looks tight.
https://www.thonhotels.com/our-hotels/norway/oslo/
Oslo is hosting a big Nor-Shipping 2017 Intl Shipbuilding exhibition and maritime conference May 30 through June 2 with 9000 delegates expected. http://nor-shipping.com/hotel/
To make it easier for our delegates to secure accommodation for the
2017 event, Nor-Shipping has blocked off rooms at many different
hotels around Oslo.Don’t wait! Large conferences such as Nor-Shipping have a way of
taking up all of the available hotel space in the city. Please reserve
your room today.
Edgar nailed it . Any city , with an impending major event will find hotels as scarce as hen's teeth . Think Oktoberfest in Munich , September , fashion season in Paris , Edinburgh in August - Edinburgh Festival , Edinburgh Fringe Festival , and Edinburgh Military Tattoo - A triple header !! hope you have some luck
If you are already locked in to Oslo during the maritime convention dates, check back after May 15th. The Nor-shipping convention will release unsold rooms after May 15th.
I just checked May 30 - Jun 2 on Airbnb and there are quite a few places available...have you considered this option?