Gluten Free diet/cuisine in Spain and Portugal

I have celiac. I spent 3 weeks in Portugal last year with absolutely no problem. As they mostly make seafood and vegetables fresh/from scratch they were very knowledgeable, helpful and accommodating when I mentioned I needed gluten-free. Helpful at highlighting options and reworking dishes if need be.
Some places even made me GF croissants or bread! Which was unexpected and so kind. There were plenty of options. Alas, you will miss out on the bacalhau (maybe that's ok) and desserts unless someone can advise you about a gluten free bakery. Don't worry much. Have a great time!

Thank you very much for the insight information and your positive experiences. I find that people are generally nice and kind when we ask or talk about foods. I appreciate your response. Thanks again kindly. Ttay

Will you be visiting Catalonia?

If so,
https://www.celiacscatalunya.org/ca/index.php
https://ajuntament.barcelona.cat/comerc/en/current-news/city-council-launches-new-guide-gluten-free-restaurants-certified-coeliacs-association
https://wheatlesswanderlust.com/gluten-free-barcelona/

Use google translate where appropriate.

When I was in Spain in 2017, I also research GF. They have a pretty robust menu identification system with icons, so easy to pick out. I tend to eat my largest meal at lunch or grab a Spanish tortilla (a dense potato omelette) as street food. If you have apartments, I found the little corner Carrefour grocers had a reasonable selection of GF options. I am not a fan of the thick puffed rice crackers I hsve access to in Canada, but Carrefour carried thin ones I enjoyed. With some peanut butter, a quick snack or breakfast. I didn't even attempt tapas, but the daytime options were always on bread and I was never out late enough for a wider variety.

Try using the app try me gluten free (GF). It's essentially crowd sourced, so not necessarily complete. Still helpful.