Mew is only obtainable in Pokémon Go through completing a series of quests titled “A Mythical Discovery.” The long quest line can be found under the Special Research Tasks tab.
Unlike Celebi’s quests, Mew’s don’t require too much preparation in advance. The only thing you’ll want to save up, other than a handful of berries, is Magikarp candy. One task involves evolving a Magikarp, so if you’re planning on getting a Gyarados soon, you should wait until you reach that task.
Seriously, do not evolve a Magikarp until you’re at this quest step. It requires 400 candies and getting another 400 when the quest comes up will absolutely suck.
All eight steps to Mew’s “A Mythical Discovery” quest line is listed below:
• Spin five Pokéstops
• Catch 10 Pokémon
• Transfer five Pokémon
Reward: 10 Great Balls, an Incubator and three Lure Modules
• Earn two candy walking with your buddy
• Make 10 great throws
• Hatch three eggs
Reward: 2,000 Stardust, three Incense, and 20 Great Balls
• Reach trainer level 15
• Battle in two raids
• Battle in a gym two times
Reward: A Fast TM, a Charge TM, and two Star Pieces
• Earn the Kanto Silver Medal
• Evolve 20 Pokémon
• Earn five candy walking with your buddy
Reward: 4,000 Stardust, three Lure Modules, and 20 Great Balls
The Kanto Silver Medal requires catching just 30 Pokémon from the Kanto region. You should get this without even trying.
• Catch a Ditto
• Catch 10 ghost-type Pokémon
• Make 20 great throws
Reward: A Premium Raid Pass, a Lucky Egg, and 15 Revives
Catching a Ditto is essentially a crapshoot. Random Poke
• Reach trainer level 25
• Evolve a Magikarp
• Battle in 10 raids
Reward: 6,000 Stardust, five Rare Candies, and three Incense
• Catch 50 Pokémon using a berry
• Earn a Kanto Gold Medal
• Make an excellent curve throw
Reward: 8,000 Stardust, five Great Balls, and Mew encounter
The Kanto Gold Medal requires catching 100 Pokémon from the Kanto region. You can keep track of your total on the top of your Pokédex.
• Catch Mew
Reward: 10,000 Stardust, a Super Incubator, and 20 Mew candy
Once completing all the steps, Mew will pop up with AR on and unlimited plain Pokéballs handy. Mew moves around a lot, but don’t worry too much about landing excellent curve balls. Mew will eventually be caught, as long as you hit it with balls.
Mew isn’t a very good attacker for raids or gyms, but can learn an extremely versatile number of moves. However, players will need a massive amount of TMs to make Mew work to their favor, making the cute Legendary Pokémon more of a Pokédex filler than anything else.