Prefer X to Y / Prefer to … rather than … / Prefer X than Y
UsagePrefer normally compares things with to: prefer X to Y. When comparing actions, prefer to do X rather than do Y is also standard.
Prefer X to Y
Use when
You compare two nouns, noun phrases or -ing forms and favour the first.
Example
“I prefer option A to option B.”
Prefer to … rather than …
Use when
You compare two actions expressed as infinitives.
Example
“I would prefer to defer the launch rather than rush the decision.”
Prefer X than Y
Use when
Avoid than directly after prefer when comparing two things in the standard prefer X to Y construction.
Example
“Replace 'I prefer option A than option B' with 'I prefer option A to option B'.”
Quick check
prefer A than B, prefer X more than Y where X and Y are directly compared, preferred than
Usage note