Bella Swan fully becomes a vampire at the end of Breaking Dawn (book 4) right after giving birth to Renesmee, when Edward injects her with his venom and she completes her transformation over three days.

Quick Scoop: When does Bella turn into a vampire?

In the Twilight saga timeline, Bella’s transformation happens very late in the series, not in the early books. She is turned only after her pregnancy nearly kills her, and Edward has no other way to save her life.

In the books

  • The actual turning happens during the traumatic birth scene in Breaking Dawn.
  • Edward injects venom directly into her heart and then bites her in several places to speed up the change.
  • Bella’s heart stops and she endures about three days of burning pain before she wakes up as a newborn vampire.
  • In the internal saga timeline, fans place the start of her change around September 11, 2006, and her waking as a vampire on September 13, 2006.

In the movies

  • In The Twilight Saga: Breaking Dawn – Part 1 , Bella starts turning on the operating table immediately after Edward injects his venom post–C‑section.
  • The full “newborn Bella” reveal (red eyes, enhanced senses, new powers) is then explored in Breaking Dawn – Part 2.

Extra context fans discuss

  • Bella has wanted to become a vampire since early in the series, but Edward puts it off for years because he fears damning her soul.
  • Her transformation is portrayed as unusually controlled for a newborn: she has strong self‑control and a powerful mental shield ability that becomes a full-blown defensive power as a vampire.
  • Fans often debate whether she should have been turned earlier (e.g., after Eclipse) versus saving it for the climactic birth scene; most agree the late change raises the emotional stakes of the finale.

TL;DR: Bella turns into a vampire only at the very end of the main story, in Breaking Dawn , right after Renesmee’s birth, completing her three‑day transformation and waking up as a newborn vampire.

Information gathered from public forums or data available on the internet and portrayed here.