Ferry to Spain

Have you seen the prices? Don't assume it will be cheaper, you must factor in eating during the crossing, fuel to your destination and possibly an overnight stop, then double that for the return journey. 

There is the "Club Voyage" scheme that Brittany Ferries run, but this has recently been changed, again you will have to make up your own mind. 

I use it at least once a year because it's convenient for me, but it's not cheaper than flying. 

Do your research. 

P. S. It's a pleasant crossing and an easy drive. 

The ferry used to be reasonable priced, not now, we ended up buying Spanish car and using cheap flights.

If taking kids take something to occupy them as internet on the ferry is also expensive. Would agree its a nice crossing assuming the weather is good.

Unfortunately  Concession  are  done  away  with,  It approx  9  hours  drive  to Playa Flamenca  from Bilabo, I  drove  down  recently, and  tried  to avoid  Toll  on  exit from  Bilabo  port, but  failed   12  euros  to  Burgas , that  was only Toll I encountered ,

Traffic  North of Madrid  was very heavy  and it was early  Sunday morning, 

Ship are comfortable  enough   Do  not purchase  Marine  time  Internet  on board expensive  and  hit and  miss, 

Food  on  Board is adequate  but I  found  it a bit  pricey, I  would  suggest  you bring  plenty  of  Drink  water and Fruit on  board with  you,  There is 4  beds in a Cabin  and you also got  recliner  chairs  in a  lounge  for  sleeping  😴   but I  have never  used them  as   had  a  long  drive ahead of  me, also  if  young  kids using  them, getting  some  sleep  might  prove  difficult ,  I  used Car Ferry  as staying  for  2 months +,  so Car hire  out of question 😀 

That  my  personal  experience 

I understand but if I'm traveling by plane, I will have the additional high car hire costs. It'll still be cheaper I think.

Regards 

I  will  add  that  if  any  Storms  about, The Bay  of  Biscay   can  be  very  Rocky,  I  encountered  a  stormy  crossing  and  walking  on board was not  advisable,  

I suppose it depends how many people are travelling and how long you're staying in Spain. I would suspect that it's cheaper and less hassle to fly and hire a car if your visit is only for 2 or 3 weeks.

You can see the Brittany prices for the Portsmouth to Bilbao crossing online. Just remember that there's no longer any discounts and you need to add the cost of the cabin(s). You'll probably need some accomodation enroute unless you time your arrival in Spain for the early morning (The Sunday night route used to be good, set off at 10.30pm and arrive at 08.00am a day later. 2 nights on board). It's a 10+ hour road trip if you're doing it in one day.

We've done the trip many times and enjoyed the adventure but we now have a car in Spain so flying is easier and so much cheaper.

Good luck.