I heard that the soft opening will be 3 weeks before. That would make it May 28th the day the packages start.
First, the release date. It was confirmed to us that the grand opening for the Wizarding World of Harry Potter at Universal Studios will take place on June 18, 2010. This information was made available to fan sites first and will be announced at some point later today (March 25th). Interestingly, the Universal Orlando Resort has been offering vacation packages beginning May 28th, 2010 which offer admission to the park and breakfast in The Three Broomsticks. Two separate sources at Universal confirm that this vacation package, which is still available from Universal Orlando’s web-site and will continue to be available, is legitimate and will be honored. Those who opt to buy the vacation package and travel on May 28th will get what they’ve paid for. This means, technically, if you choose the package you will be among the first to visit and see the park.
Also confirmed by a Universal representative, the notion of a “soft open” or a preliminary period of the park being open to the public before the grand opening of June 18th is sound, but no specific dates are known at this time. So there will be opportunities for guests to access the park prior to the grand opening week, particularly by way of purchasing this “early access” vacation package mentioned above.