I would guess that some intra continental communications still use sub-sea cables, either through necessity (UK to France) or to cut out a large number of hops

I would guess that some intra continental communications still use sub-sea cables, either through necessity (UK to France) or to cut out a large number of hops (say South Africa to the Ivory Coast; I don't know if such a cable exists, but I think there are cables going alongside west Africa).