How to Get Glaceon in Pokemon GO is the same as getting any of the Eevee-lutions.
Glaceon is an elegant ice-type introduced Generation IV as a new branch of the Eevee-lutionary tree -- alongside its grass-type counterpart, Leafeon. Its PokeDex number is 471. Also known as the Fresh Snow Pokemon, Glaceon has the power to "freeze the fur on its body, and make it stick out like sharp needles," according to the PokeDex. It has quickly become one of the more popular evolved forms of Eevee.
How to Get Glaceon in Pokemon GO
In Pokemon GO, there are a few ways to get Glaceon. The quickest of these is to evolve an Eevee.
The first way to evolve Eevee into Glaceon involves a special Lure—the Glacial Lure. Setting up the Glacial Lure and standing near it will prompt the Eevees within range to evolve into Glaceon when selected. Trainers can double-check this by looking for a Glaceon silhouette on their chosen Eevee's "Evolve" button.
This is likely a callback to the mainstream games where Glaceon was only available through overland evolutionary stones. Gen. IV's Sinnoh region had specific spots hidden away where players could bring their Eevee to evolve it into either Glaceon or Leafeon. Further installations have now have introduced a standalone item similar to the Fire or Water Stone for Flareon and Vaporeon, respectively.
If you don't have a Glacial Lure, aren't near a PokeStop, or simply can't be bothered, you can also try to the naming trick. Every Wevee-lution has a specific nickname that corresponds to their form. When an Eevee is given this nickname and evolved, it turns into the evolved form—but this only works once.
Glaceon's nickname is "Rea."