When therefore I have completed this and have delivered to them what has been collected, I will leave for Spain by way of you.
Romans 15:28 ESV

We know from Acts 21 and onward that Paul was able to come to Rome eventually, but not on his way to Spain. His missionary trip to the Iberian Peninsula was interrupted by his arrest at the Temple in Acts 21:33. There is some debate about whether he was imprisoned in Rome once or twice and if he might have journeyed to Spain--or even further--in between. There are some traditions of Paul visiting Span and Britain, but no solid evidence.