Certainly along the Algarve you would expect to encounter Bass, Little Tunny and Bluefish among other species. They may also extend further northwards along Portugal's Atlantic seaboard.
There are a few boats at Villamoura (on the Algarve) but I suspect most will be geared up to taking tourists out for Blue Sharks, or the very occasional White Marlin. The whites are not there though in sufficient numbers to consider tossing a fly at them. You may though, certainly further westwards find a local with a small boat prepared to take you out under the cliffs. But they would certainly be untutored in fly fishing. Shore fishing in some of the coves on the Algarve is also feasible, but watch the big swells on the Atlantic side.
Any flies that work in Ireland should work with small Deceivers or Clousers (fry pattens) for the Bass.
In freshwater a number of the lakes and dams would have been stocked with Largemouth Bass and Trout.
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