Disneyland was the last Disney theme park to attempt reopening, and while it took the longest for guests to return, the park was closed for over a year, it has moved much faster than the others when it has come to adapting its rules and returning things to normal. When the parks opened at the end of April, they were only open to residents of the state of California. However, out-of-state guests won't have to wait too much longer to get their time at the happiest place on earth, as Disneyland Resort has announced that all guests will be welcome inside the gate beginning June 15.
June 15, had already been announced as a big day for the state of California, a sort of statewide "reopening" when a lot of pandemic related restrictions are set to be lifted. That also includes a number of theme park related restrictions and Disneyland Resort will be taking full advantage of the opportunity. Disneyland will be ending on-stie temperature screenings on June 15 as well and the parks will be able to increase capacity.
Technically, out of state visitors who were already vaccinated were allowed to visit theme parks according to California guidelines. However, while others parks like Universal Studios Hollywood made the move to allow those that were vaccinated to visit the parks, Disneyland had held on to the "California-only" rule. Disneyland was having little problem filling its limited capacity with California residents, and so likely felt little need to expand the pool of potential guests considering the park would need to verify vaccination, which likely would have been complex.
While those out of state guests may be welcome in the middle of June, they may have to wait until July to actually visit the parks. Currently, both Disneyland park and Disney California Adventure park are at capacity nearly every single day for the rest of May and all of June. There are a few days where access to one park is available but if guests want to visit both parks on their trip, as one assumes they will, they'll need to push the trip into July.
In addition to allowing more guests in the park, Disneyland Resort has also extended the dates that guests can book. The parks had been giving people the ability to reserve park dates 60 days out, but now the calendar is open 90 days in advance, giving people a bit more flexibility when it comes to booking.
Disneyland's Paradise Pier hotel will be reopening on June 15 as well, which is perfect timing as the park will likely see even more people in need of hotel rooms beginning at that point. The Disneyland Hotel will follow on July 2 and at that point all of the resort's hotels will be open to guests.
Technically, Disneyland will be allowed to increase its capacity to full once June 15 rolls around, though all indications are capacity will increase more slowly than that. Exactly when full capacity will be reached, or when massive crowd events like fireworks will return, we don't know yet.