In Stranger Things Season 1, the characters “get Will back” in the final episode, when Joyce and Hopper find him in the Upside Down and resuscitate him.

Quick answer

  • Will disappears in Episode 1 of Season 1 (“The Vanishing of Will Byers”).
  • He is rescued and brought back to the real world in Episode 8, the Season 1 finale (“The Upside Down”).
  • In the show’s in‑story timeline, Joyce and Hopper find him on November 12–13, 1983, and bring him home.

A bit more context

  • Will spends most of Season 1 trapped in the Upside Down, hiding in places like the Upside Down version of his house and Castle Byers while the Demogorgon hunts him.
  • His friends and family only see brief signs that he is alive (lights flickering, phone calls, visions) until Eleven locates him remotely and Joyce/Hopper physically reach him.

After he comes back

  • Even after they get Will back, he is not completely “okay”: at the end of Season 1 he coughs up a slug and briefly flashes back to the Upside Down, hinting that something of that world is still inside him.
  • That lingering connection becomes a major plot point in Season 2 and later seasons, where Will can sense the Mind Flayer and Vecna because of what happened to him while he was missing.

TL;DR: They get Will back in the Season 1 finale, when Joyce and Hopper rescue him from the Upside Down and revive him.