Catching permit on the fly is one of the most challenging things you can do while fly fishing the flats.  To consistently catch permit on the fly, you need to travel to some of the destinations that have large numbers of permit on the flats, a good guide or partner that can help to put you in a position to make a good cast and most importantly, making an accurate cast that doesn’t go too long or fall short.  Permit spook so easily and they can be so finicky that catching them on the flats with a fly may seem impossible to some fishermen.  It is possible though with some patience and skill.  Many fly fishermen insist that you need to be fishing with Del Brown’s Merkin Crab Fly if you want a chance to catch a permit on the fly.