30 once synonyms include One time, At one time, A single time, Formerly, Previously, In the past, On one occasion, Back then, Sometime, and At one point. Once is an adverb, and its antonyms are twice and many times. Here are some additional synonyms for "once" with example sentences.
30 other ways to say once.
Call me once you finish everything.
Every achiever was once a beginner.
Her appearance surprised everyone at once.
I zonked quickly once I hit the pillow.
once you're ready, let's begin.
She smiled once she arrived.
The tree blooms once every five years.