The heir to the Norwegian throne enjoyed sunshine as temperatures soared above 20 degrees celsius over the weekend.
The celebrations were more modest this year than last. In 2013, 220 friends and family celebrated his 40th birthday with a special festival in Skaugum.
Crown Prince Haakon was joined this year again by his wife, Crown Princess Mette-Marit, and their children Ingrid Alexandra, Sverre Magnus and Marius.
The family regularly spend summer in their countryside residence on Dvergsøya and it was here they gathered with guests on the date for the birthday party.