Pokemon Sword & Shield has 6 Legendary Pokemon. This guide shows how to get all Legendaries in Pokemon Sword and Shield.
Eternatus is automatically caught during the story. Near the end of the story you will have to fight Eternatus in a Max Raid Battle. After defeating it, throw a Pokeball and it’s a guaranteed catch. You get a lot of help from your friends during this battle so it’s not all that difficult.
Zacian und Zamazenta
They are caught in the endgame / post-story episode. After beating the story, you will have to return to the shrine in Slumbering Weald where you found the Sword and Shield artifacts. Hop is waiting there and wants a rematch, defeat him and then defeat the other trainers that show up. Afterward, visit Sonia’s Lab in Wedgehurst and she’ll give you a device to spot Dmax Energy. Go to Turffield Stadium and you will learn that Pokemon have started to Dmax on their own within Stadiums. You must go back to all Stadiums and defeat a Dmaxed Pokemon in each (except Spikemuth). After you defended all Stadiums, talk to Sonia in the entrance hall of Hammerlocke Stadium. She opens the elevator next to her, which leads to the Energy Plant. Defeat the trainers in the Energy Plant and you’ll be brought to the rooftop. Zacian (Sword) / Zamazenta (Shield) are automatic story encounters on the Energy Plant Rooftop at the end of this post-story episode, you can’t miss them. They are very hard to catch and can quickly defeat your own Pokemon. It’s recommended you use the Master Ball here that you got from winning the Championship. Beware that Sword players will first fight a red glowing Zamazenta which cannot be caught, and Shield players will fight a red glowing Zacian first which cannot be caught. The second fight will be versus the Pokemon that’s exclusive to your game edition and at this point it can be caught (you can tell because it doesn’t have the red energy around it and will wear the Sword or Shield relic).
Type: Null & Silvally
Type: Null and Silvally count as legendaries, too! After finishing the story, travel to Wyndon and enter the Battle Tower there. Immediately after going inside, turn left and talk to the girl with Type: Null next to her. She will gift you this Pokemon!
To evolve Type: Null to Silvally, you must increase its happiness value to 220 (play with it at camps and cook curry). Then it will evolve. They are a bit more secret than the other legendaries as they can easily be overlooked and aren’t such obvious legendaries.
To obtain Mew you must buy a Pokeball Plus (can be purchased separately). This gadget allows you to transfer Mew into Sword and Shield. However, if you already used this for Pokemon Let’s Go, you won’t be able to do this (must buy a new Pokeball Plus in this case).
That’s how you get all 6 Legendaries in Pokemon Sword & Shield.