Pokémon GO is introducing an age-old mechanic from the Pokémon franchise called Trade Evolution. Some Pokémon will only evolve if you trade them with another trainer, but things work a little different in Pokémon GO.
The Trade Evolution mechanic is straightforward. You have the second form of a Pokémon in your collection and ask a friend to trade with you. When you trade, your Pokémon goes to your friend. When it arrives at them, the Pokémon has no candy cost to evolve. If you already received any of the Pokémon who can evolve through trades in the past, they will have no candy cost to evolve.
It’s important to remember that in Pokémon GO, you cannot trade a Pokémon more than once. If you trade that Pokémon to your friend, it goes to them and stays with them. It means your friend needs to send you the trade if you want it to cost lost to evolve the traded Pokémon.
This method doesn’t work for every Pokémon. Here are the ones that benefit from it:
If you have any of these Pokémon in your collection, reach out to one of your friends to start trading with them. This mechanic should assist trainers looking to save up candy with these Pokémon who want to use it to level them up and make them stronger. Because you can only trade it once to another trainer, you need to be careful about what you trade and what your friend gives you in exchange.
We can expect this list of Pokémon who can evolve through trades to grow in the future. It is a brand new mechanic to Pokémon GO, but a standard one since the Pokémon Red and Blue. Because it’s a brand new system for Pokémon GO, we can’t expect too many Pokémon to have this, but we can expect developers Niantic to slowly introduce more and more as time goes by.