Stefano, Zanzibar from Dubai.
A friend dived there a couple of months ago.
But the only issue, for me, is that majority of dive centers only do two dives a day.
This may not be an issue since you will have company. When I travel for diving, I like to do at least four dives a day.
Sure, I could read a book, sun bathe, take a walk, or whatever at one pm after the second and last dive of the day.
But I prefer not to. I can do all those things at home.
The two reasons for two dives a day in Zanzibar are it being more of a resort-destination than a dive-destination and because of the daily low tide which hinders most dive centers from launching the boat from the shore.
My friend said most days, on return after two dives, they'd dock at the harbor and then take a minibus back to the hotel.
In the meantime, the east coast (from Fujairah all the way up to Dibba) is only a casual two point five hours from Abu Dhabi.