Eventually, I got the White River Knives FC4 I posted about earlier. After reading up on the knife laws it's clear to me I won't be taking any knife to the beach, or club, but I will be doing some hiking and such and it will come with me. Also, the place I rented is apparently very very basic, so I think it'll help me around the kitchen. I also like that I could easily reverse the sheath for left-handed carry. It seems like the kind of knife that I will be enjoying for more than one trip.
This will be the most expensive knife I'll take on this trip. Other than that, I'll take a SAK (Vic Huntsman) and an opinel stainless. I'm still debating on whether I'll take a small axe and folding saw. I do like whittling though. I think I'll see if there is any space left in my pack while packing.
I think this combo strikes a nice balance between my needs and also the cost involved. I've saved up a little money so if I come across a great knife there, I can still buy it. I'm not sure what to expect, but it might be fun to hunt around a bit.
I've also looked at the Canary Island knife
cbach8tw
mentioned. I'm gonna see if I can find anything about it there, but I think I might be on the wrong island. We'll see.
I've also very much enjoyed checking out the other recommendations in this thread and a lot of them have made it to my wishlist.
I concede that the combination of spanish knife laws as well as my own strange tastes have narrowed my selection down in a strange direction, but I am very glad with this thread and I hope it will be a resource for others in the future. With that in mind, do feel free to keep recommending good knives for travels near the sea.
All that remains is to once again thank you all for your suggestions and input! It really helped me out!