Barcelona to Perpignan

Take the train from Barcelona station. It's a 1.5-hour, direct journey.

You can travel with the Spanish train company Renfe or the French company SNCF.
A 2nd-class ticket costs around €50, depending on the date.

https://www.sncf-connect.com/en-en

https://www.renfe.com/es/en

I would be very cautious about using Rome2Rio. It has often delivered wildly off-base results. I do check it sometimes to identify bus companies serving a particular route, though the info isn't totally reliable. After finding the name of the company, I go to its website for schedule and fare information.

Jolui gave the correct information. Unfortunately, Rome2Rio is no longer updated and reliable.

I have taken it down. No more rome to rio. Got it.

Thanks - all - for your input. - Mary