Not the same station, seems like doable walking distance. 20 min walk. About a km.

Any map would have given this answer. It appears to be a situation where one station is the old one, and a newer station nearby with its underground tracks for high speed trains, like Lille Flandres vs Lille Europe. 

Out of curiosity: was the train planner you used clever enough to give travel options where you would be switching transferring by foot between the two stations?

Just for the record, I did look it up on Google maps:

But it didn't look convincingly as a train station. 

The rail planner suggested to leave the direct train changing at Pontevedra waiting an hour for a regional train going to Vigo Guixar. So not smart enough to suggest to walk.

For future reference it is definitely worth it to walk from Vigo Urzáiz to Vigo Guixar instead of changing trains like the rail planner suggests. It is a quick walk down the hill.