5 or 6 weight outfit, floating line, and a Sawyers Killer Bug. It represents a maggot, which the Mullet feed on as the tide covers up the sea wed (where maggots are wriggling) You only need to cast a few yards out.
Mikes suggestion of bread qand "bread" fly..basically a bit of white marabou, is great if they are in a harbour:)
Good luck!! and let us know how you get on.