Two weeks ago I took a day trip to Gijon, Spain (I was staying in Oviedo). I was there all in around 6 hours. Honestly think that was plenty of time, unless you were there for the beach.
Photo 1: Gijon sign. Walked past this on the way into the city from the train station.
Photo2: View of old town as I continued my walk towards the city.
Photo 3: View of the sea after walking up, and up, and up, to see the Fuerte Viejo y baterías de Santa Catalina - it gives you a nice elevated view of the sea, the coastline, and the city on either side.
Photo 4: Walking down the other side on the trail from seeing the Fuerte Viejo y baterías de Santa Catalina this view is of San Lorenzo beach area.
Photo 5: View out to the sea (and looking towards where the previous picture was taken by the seaside church). I was on San Lorenzo beach when I took this photo. You can see a surfer out in the water. Was quite a few of them.
Photo 6: Cool mural on the side of a building across the street from San Lorenzo beach.
Photo 7: The Cider Tree. This is in the old town area and is made up of the famous cider bottles.
Photo 8: Parque de Begoña - this was around a 13 minute walk from San Lorenzo beach.
All I knew of Gijon before my trip was the beach scenery. What I didn't realize is that Gijon has 3 beaches and San Lorenzo is the famous one. The other two were kinda meh. First one was a more industrial part of town and second not much better.
If you arrive by train, the main train station is essentially on the outskirts of the city and you end up walking through a less nice part of Gijon. There were a lot of homeless people by the station and it felt safe in the day time.
There is no Uber or Cabify in Gijon. Tried using FreeNow taxi app, which is in use there. Wanted to get a taxi from Parque de Begoña to the train station but literally no one would accept the ride so we ended up walking.
It wasn't super warm when I was there and I didn't see a ton of other tourists. I suspect it gets busy in the summer and that there's a lot of people who go there for the water sports.