Dive into History
When these pages are complete (hopefully soon) then each of these boats will have its own "Dive" page with photos, maps, and contact information. Until then, the links simply link to the respective U-boat profiles.
Today I am not aware of any certain dive sites around Portugal but several boats were sunk / scuttled in these waters including;
U-1277 is a regular dive just off Oporto, Portugal. She is at 30m depth.
You can get more info at this site.
The boat was scuttled at 1000hrs on 20 May, 1945 on the Portuguese west coast near Nazare in position 39.36N, 09.05N.
Recent information suggests this boat has been located at the depth of more than 100m but she will never be a dive site due to unfavorable conditions. At this depth it's beyond the range of even the best divers.