Slowpoke entered the Pokemon series with one lone evolution, but along with its Galar region counterpart, it now has more than a few evolutions.
In Pokemon GO, evolving Slowpoke and Galarian Slowpoke requires certain conditions to be met in all but one instance (evolving Slowpoke into Slowbro). These requirements vary from the use of evolution items to catching specific Pokemon while using the Buddy System. Regardless, it will take some dedication not only for trainers to evolve Slowpoke, but to obtain all of its forms from both the Kanto and Galar variants.
Pokemon GO: Evolving Slowpoke and Galarian Slowpoke
When evolving the Kanto version of Slowpoke in Pokemon GO, things aren't too difficult to begin with. Evolving Slowpoke into Slowbro simply requires that it is fed 50 Slowpoke candies. However, to obtain Slowking, players will also need to provide an evolution item known as a King's Rock. This item can be found on an infrequent basis by spinning the photo discs of Pokestops, similar to other evolution items such as Sun Stones, Metal Coats, and Dragon Scales originally introduced in Pokemon's Johto region.
For Galarian Slowpoke, evolution requires a much more time-consuming path. To evolve into Galarian Slowbro, trainers will need to buddy up with their Galarian Slowpoke and capture 30 Poison-type Pokemon before feeding it 50 candies. This tactic is similar for the evolution into Galarian Slowking, which requires 30 Psychic-type Pokemon while buddied up. The good news is that the Galarian evolutions don't require evolution items, but the argument could be made depending on a player's environment that catching 30 Psychic or Poison-type Pokemon can be a taller task. Unlike Pokestops, which are set in one location, the spawning behavior of Psychic and Poison-type Pokemon change depending on location, some of which can be difficult to find in certain parts of the world for Pokemon GO trainers.
There is one final evolution for standard Slowpoke which is its Mega Slowbro form. This form can be used to take on raid bosses, providing a significant boost in power and resulting in an above average fighter despite being one of the weaker Mega Evolutions. In order to evolve a Mega Slowbro in Pokemon GO, trainers will need to accrue Mega Energy that is normally collected after beating the appropriate Pokemon as a raid boss. This means Mega Slowbro Energy is likely to be scarce due to the rotation of raid bosses, so Pokemon GO players should stock up as much as possible for when they need it most.