I had a day spare after completing both legs of the Camino Ingles in 2009 ,so I returned to La Coruna to see the Tower of Hercules.
I have never been more disappointed in my life as the outside is clearly not the original. Roman? Bah.
I didn't bother going inside because I had nowhere to leave my rucksack.
Don't let my experience stop you but if you do go let us know how you felt about it.
I have met several people who also felt the same as myself.
ps, if doing this again, I would go to Ferrol and spend the rest of the day there. I found it much more interesting, but as I had decided to arrive mid morning and then walk straight out I only caught brief glimpses of the town.
Can I confirm Sojourner's observation that it takes 40 minutes to walk from the Ferrol bus station to the harbour. In June 2009 there was not a taxi to be seen anywhere. You will need to also allow time for photos, stamping of the sello etc. If you arrive from A Coruna all of this would add up to a late start out of the town. It is 11km to the Neda albergue, 25km to hotel accomodation in Pontedeume and 38km to the Miño albergue.
Depending on your pace and where you intend to spend the first night will obviously influence your final decision.
If you arrive at Ferrol late in the afternoon you can collect your sello, sightsee, have a night in a hostal, then return to the harbour and make an early start, fresh and rested.
Would be interested to have others point of view.