There are no clubs in Ayia Napa which have an official dress code. Some of the more sophisticated clubs such as Soho or Castle have a "dress to impress" policy. 

It's very hot in the summer in Ayia Napa and the nights are barely cooler than the day so don't bring heavy clothing. If you're going to Foam Parties or paint parties, don't wear your best clothes as they will get ruined. 

If you book bar crawls or other events you'll get a free T-shirt which is perfectly acceptable to wear on a night out in Ayia Napa. 

Nudity isn't acceptable on the streets of Ayia Napa. Save the skin for the beach and make sure you're wearing something!

In May and October in Ayia Napa you may find it a little cool in the evenings so you may need a jumper/cardigan or light jacket. 

The streets in Ayia Napa are a mix of cobbles, paving and concrete so if you choose to wear high heels, be aware that the road surfaces are not even.