As a Swans fan (living in in Totton 10 years, and Saints member), I hope you have a great day. You should be most welcome.
Remember, Swansea are NOT Cardiff. Far from it . . . . . .
No tickets on Sale on the day for away fans (it's complicated and idiotic, but there you are), so get your ticket in good time.
Official bus is best option. Virtually zero parking nearby. There is some sort of away park and ride i think, but you'd have to check online.
Stadium not in most salubrious area of Swansea, ahem, if you get my drift.
You probably won't get into pubs near stadium if wearing colours.
If wearing colours and alone, avoid Rossi's chippy near stadium. Pond scum who have no connection to football club may be nearby looking to smack you. Danger begins and ends there, unless you want to play Billy Big ********, in which case . . . . you know how this ends.
If you want pubs in town before the game, make for Wind street (as in winding in a fishing line, not the gale force type). Left out of station.
One of two games of the season I won't be supporting the saints
ATB