Mexico is a casual place. Time is less important, schedules are flexible, and high fashion doesn’t mean the same thing as it does in Paris or Milan. Keep that in mind when packing for a vacation in Playa del Carmen. Leave the suit and tie at home, and keep that Vera Wang cocktail dress in the closet. When everyone else is feeling cool and comfortable in their laid-back attire, your entrance in designer clothing will cause awkwardness for those around you.
Your wardrobe for Playa del Carmen should have one purpose beyond covering the body: comfort. Comfort in keeping you cool and unrestricted. Excluding jeans, linen and lightweight cotton blends are ideal to pack. Considering the level of humidity, and the high temperatures in the tropics, denim garments are a silly choice to wear. Stick to lightweight weaves that do not cling. The more air flow there is around the body, the cooler you will be.
In terms of swimsuits, use your modest ones. Overly skimpy swimsuits and bikinis are not appropriate for a place you will be sharing with other travelers from all over the world, and who will have different ideas about modesty. Save the string bikinis and thongs for the private pool at home. Also, remember that you are visiting someone else’s hometown. Be respectful of the modest views of locals. They bring their families down to the beaches on the weekends too.
Contrary to the chatter on the Mexico forums, the beaches of Playa del Carmen (and indeed all beaches in Mexico) are not ‘clothing optional’ beaches. Sometimes a bit of discreet topless sunbathing is done by women at Playa del Carmen, however, one tip from their online travel guidebook states: “the further north from the ferry dock you get, the less clothing you’ll see”. You may want to stay in the southern area of the beach if behavior such as this makes you feel uncomfortable. Generally speaking, nudity is rare.
Even if you never wear hats at home, wear a hat in Mexico. The sun is very intense in Mexico, as it is much closer to the earth than in more northern regions. Sunburn, heat stroke and severe dehydration occur much faster in Mexico. A hat (along with proper hydration) provides an important barrier between the sun and your body. Try to choose one with a brim all the way around, and with breathability.
When packing for Playa, remember two things: comfort and respect. Dress neatly, appear well kept and clean. Make sure you respect the sensibilities of the locals while you also try to stay cool.