The new Space Marine codex has not been given a firm release date in the sources I found, but current Warhammer 40,000 coverage shows the new edition launching in June 2026 and says Space Marine faction packs were already available on June 9, 2026. The latest official preview instead highlights Orks as the first codex of the new edition, so a Space Marines codex date has not been publicly pinned down yet.

What’s known

  • Warhammer Community said the new edition of Warhammer 40,000 is launching with a boxed set on Armageddon and that Space Marine faction packs were available on June 9, 2026.
  • The big summer preview on June 25, 2026 said the first codex of the new edition is Orks, not Space Marines.
  • Secondary coverage from June 26, 2026 also points to new Space Marine content in the launch wave, but not a codex release date.

Practical read

That means the safest answer is: no confirmed release date yet for the new Space Marine codex in the material currently available, but it looks like Space Marines are part of the launch cycle around the new edition’s June 2026 rollout. If you mean a specific chapter codex or supplement, the timing could differ from the main Space Marines book.

TL;DR

The new Space Marine codex appears to be unannounced so far , while Orks are confirmed as the first codex for the new edition and Space Marine faction packs are already out.