What should I pack for Cancun?

Reef-safe sunscreen is not optional in Cancun. Quintana Roo state law bans oxybenzone and octinoxate-based sunscreens at beaches, cenotes, and eco-parks like Xcaret and Xel-Ha. Rangers at Punta Nizuc, part of the national marine park established in 1996, might confiscate non-compliant bottles. Buy a mineral zinc-oxide SPF 50 before you fly, because reef-safe options at Hotel Zone pharmacies run 350-500 MXN (20-29 USD) for a small tube. The Caribbean sun at 21°N latitude burns fair skin in 15 minutes. That salt breeze off the water tricks you into ignoring a UV index that sits above 11 most of June.

June through October is rainy season, and in Cancun that means a wall of warm water at about 3pm that hammers down for 45 minutes and then stops. The rest of the day tends to be 30-34°C with 65-80% humidity, the kind of thick heat that makes cotton stick to your back within 10 minutes of stepping outside. Pack 3-4 quick-dry synthetic shirts and one light long-sleeve layer for the aggressive air conditioning inside places like Plaza Las Americas and the Mayan Museum of Cancun, which opened in 2012. Restaurants along Kukulkan Boulevard in the Hotel Zone keep their dining rooms at roughly 20°C. You'll walk in from 34°C and leave with goosebumps.

Footwear trips up more Cancun visitors than anything else on this list. The limestone shelf along the coast has rough, barnacle-covered entry points at beaches like Playa Delfines and near the El Rey archaeological site. A $12 pair of water shoes saves your feet from coral scrapes that Caribbean salt water will sting for days. On land, lightweight closed-toe walking shoes handle the uneven stone paths at El Meco and the cracked sidewalks of El Centro around Parque de las Palapas. Flip-flops work poolside, not on the 2-km walk from the R-2 bus stop to Playa Tortugas when the road floods after a 3pm downpour. Three pairs for the whole trip. Walking shoes for ruins, water shoes for beaches, sandals for the hotel.

Skip packing mosquito repellent, aloe vera, and cheap sunglasses. Farmacias Similares in El Centro sells Off! Deep Woods for about 85 MXN (under 5 USD), half what you'd pay at a US drugstore. Aloe vera gel runs 40-60 MXN at any Oxxo, and you'll likely need it by day 2. Mercado 28 sells polarized sunglasses for 150-200 MXN, decent enough quality for a week at the beach. US and Canadian travelers can leave plug adapters at home. Mexico uses Type A and B outlets at 127V, same as North America. European visitors need a US-style adapter, available at the airport Sanborns for about 90 MXN.