Is it haram for an Islamic woman to be surrounded by naked men alone on a beach, despite her wearing a burka?

Salam Yes it is haram if a hijabi woman alone is surrounded by naked men on a beach if thyose men are non mehrams

I live on the southern coast of Spain and can see Morocco from my house. We have numerous nudist beaches here and in fact it´s tolerated to bath naked on any beach if you´re the nudist type. Although we have a fairly large Muslim community in this region, I haven´t seen any burqa on the beach yet...thankfully =)

Yes

Doubt it that women who wear burqa will go to beach where naked people are rolling on the sand

Islam ensures not only the safety of the woman from the men, but ALSO the men from the evil thoughts of the woman. When a blind companion of the Prophet visited the Prophet, the Prophet told his wife to screen herself. She replied that he is blind, and the Prophet said "but you are not blind". So yes, we don't want mixing either way.

Its her choice,both religiously and locally.

Fortunately i doubt if any of the men will show signs of arousal

Pretty much

Modesty isn't just about covering yourself

No. But why would she be there alone willingly? Could just be walking through to the cafe....

She and they must dress appropriately, though what is appropriate differs by gender.