Bees were added to Minecraft in December 2019, as part of the Buzzy Bees update.

Quick Scoop

  • The feature first appeared in testing before that, with a bee snapshot in August 2019.
  • The full release came later in December 2019.
  • So the simplest answer is: December 2019.

Extra context

Mojang introduced bees along with bee nests, hives, and honey-related items, making them a small but memorable update.

In short: bees joined Minecraft near the end of 2019, after showing up in snapshots earlier that year.

Detail| Date| Source
---|---|---
First snapshot appearance| August 2019| 4
Full Buzzy Bees update| December 2019| 5

TL;DR: Bees were added to Minecraft in December 2019.