To clarify, here are a few possibilities:

This special OVA provides the transition to the Destiny era:

The Legacy of Gundam Seed 51

If you are looking at episode counts on various platforms, the numbers can be confusing: Original 2002 TV Run:

Fans of the Cosmic Era often find themselves searching for "Gundam SEED 51" or its sequel’s equivalent. While both Mobile Suit Gundam SEED and Gundam SEED Destiny technically concluded their original TV runs with 50 episodes, the term "Episode 51" has become a community shorthand for the essential epilogue episodes and extended finales that were released later to provide a more complete ending. Gundam SEED: "After-Phase Between the Stars"

: This episode provides the definitive ending footage that was missing from the original TV broadcast, such as the signing of the peace treaty on the moon. HD Remaster Integration Gundam SEED HD Remaster

Extended Ending: Adds roughly 20 minutes of new footage to the finale.

Rumors and Speculation:

Seed 51 [best] — Gundam

To clarify, here are a few possibilities:

This special OVA provides the transition to the Destiny era:

The Legacy of Gundam Seed 51

If you are looking at episode counts on various platforms, the numbers can be confusing: Original 2002 TV Run:

Fans of the Cosmic Era often find themselves searching for "Gundam SEED 51" or its sequel’s equivalent. While both Mobile Suit Gundam SEED and Gundam SEED Destiny technically concluded their original TV runs with 50 episodes, the term "Episode 51" has become a community shorthand for the essential epilogue episodes and extended finales that were released later to provide a more complete ending. Gundam SEED: "After-Phase Between the Stars" gundam seed 51

: This episode provides the definitive ending footage that was missing from the original TV broadcast, such as the signing of the peace treaty on the moon. HD Remaster Integration Gundam SEED HD Remaster

Extended Ending: Adds roughly 20 minutes of new footage to the finale. To clarify, here are a few possibilities: This

Rumors and Speculation: