Irons are not permitted in passenger or crew cabins. All Carnival ships have self service laundry rooms with coin operaterd washers & driers and free use of iron and ironing boards. They do have blow driers in the cabins however some people complain that they are not very strong (do not use them so don't know).
Not all of the ships have blow dryers. I know that the Elation does not have blow dryers. If you do have wrinkles you need out of you cloths, hang them in the bath room when you take a shower or you can pick up an inexpensive sloths steamer at WalMart for about $17. I found one for DW. Be sure to take a power strip or an extention cord with multiple plugs. There is only one outlet in the cabin and the one in the bathroom is only designed for electric razors on something that pulls low amps.