Recently, the Legendary Pokémon Azelf, Uxie, and Mesprit started appearing in the wild in Pokémon GO. These Legendary creatures from the Sinnoh region are extremely rare, though, so some players may be relieved to know that as of today (May 2), these three will be available to challenge and catch in Raid Battles as well.
It was recently announced that the Legendary trio of Azelf, Uxie, and Mesprit have started becoming available via Raid Battle in Pokémon GO as of today, May 2, at 1:00pm PST/4:00pm EST. They will continue being Raid Bosses until Monday, May 27 at 1:00pm PST/4:00pm EST, giving players a little less than a month to challenge them. If you miss this opportunity, however, these three Legendaries will still spawn in the wild, as they’ve been doing, though will continue to hold onto their low spawn rate. All three will also be able to be encountered in the wild during the period of time they’re Raid Bosses also, so if you don’t care for Raid Battles, you can continue just trying to find them in the wild.
Each of these Legendaries are, at least for the time being, region-exclusive, however, with Uxie only appearing (whether in Raids or in the wild) in the Asia-Pacific region, Mesprit only appearing in Europe, Africa, India, and the Middle East, and Azelf only appearing in the Americas and Greenland. There is no word yet on when (or if) a regional rotation may occur.