After Honerva's reality-destroying rampage, Allura manages to change her heart by invoking memories of a joyful life on Altea. However, in order to repair the damage caused by Honerva, Allura is forced to sacrifice herself in order to restore the destroyed realities.

Did Allura die in the original Voltron?

While Allura might be gone from the physical world, her spirit lives on. Not in some vague “oh you'll always be with us.” No, her spirit is actually alive and well in the universe in ways we can't even begin to comprehend.

How does Princess Allura die?

She was asleep in the Castle of Lions with her servant Coran for 10,000 years, and commanded and piloted the Blue Lion of Voltron, until she sacrificed herself for the galaxy in the series finale.