Puerto Rico operates under United States federal jurisdiction as an unincorporated territory. All electrical outlets follow United States standards at 120 volts and 60 hertz using Type A and Type B plugs. Visitors from outside North America require voltage converters for devices rated at 220-240 volts. Cell phones purchased in the United States function without international roaming charges under major carriers. Visitors from other countries should verify roaming agreements before arrival or purchase local SIM cards from Claro or T-Mobile Puerto Rico networks.
The island experiences tropical marine climate with average temperatures between 80-85 degrees Fahrenheit year-round. Humidity regularly exceeds 70 percent. Lightweight moisture-wicking fabrics dry faster than cotton in humid conditions. Synthetic technical fabrics designed for hot climates perform better than natural fibers in Puerto Rican coastal areas. The Cordillera Central mountain range including Cerro de Punta at 4,390 feet elevation experiences temperatures 10-15 degrees cooler than coastal zones. Visitors planning mountain hiking require long sleeves and lightweight layers for evening temperatures that occasionally drop into the 60s Fahrenheit during winter months from December through February.
El Yunque National Forest receives between 120-240 inches of annual rainfall depending on elevation. Rain occurs throughout the year with increased frequency from April through November. Waterproof rain jackets with sealed seams prove more effective than water-resistant garments in El Yunque conditions where sudden heavy rainfall can drench hikers within minutes. Packable rain pants protect against persistent rain on trails. Ponchos catch wind on exposed ridges and provide less mobility than fitted rain shells. The forest generates rain from orographic lifting regardless of broader weather patterns. Visitors should carry rain protection on every El Yunque visit including days beginning with clear skies.
Footwear requirements vary significantly across Puerto Rican environments. El Yunque trails including La Mina Falls and Mount Britton Tower contain exposed tree roots, slick rocks, and stream crossings. Hiking boots or trail shoes with aggressive tread patterns and ankle support reduce slip risk on wet surfaces. The Camuy River Cave Park requires closed-toe shoes with non-slip soles. Flip-flops and sandals are prohibited inside the cave system. Beaches including Flamenco Beach on Culebra Island and coastal areas in San Juan accommodate sandals and water shoes. Bioluminescent bay kayaking tours in Mosquito Bay on Vieques Island or Laguna Grande near Fajardo provide water shoes or permit bare feet in kayaks. Old San Juan historic district contains uneven cobblestone streets laid during Spanish colonial period starting in the 16th century. These blue-tinted stones called adoquines become slippery when wet. Flat walking shoes with textured rubber soles provide better traction than smooth leather soles or high heels on adoquines.
The Atlantic Ocean north coast generates rougher surf than Caribbean Sea south coast. Snorkeling equipment proves useful at Culebra National Wildlife Refuge beaches and La Parguera reef systems. Visitors can rent equipment from beach vendors but personal masks ensure proper fit and sanitation. Prescription mask inserts accommodate vision correction needs that contact lenses may not address in saltwater environments. Reef-safe sunscreen without oxybenzone and octinoxate protects marine ecosystems. Puerto Rico legislation restricts certain sunscreen chemicals near coral reefs though enforcement varies. Formulations with zinc oxide or titanium dioxide as active ingredients meet reef-safe standards.
Sun protection requires multiple approaches in Caribbean latitude between 17-18 degrees north. UV index regularly reaches 10-11 classified as very high to extreme exposure category. Sunscreen with SPF 30 minimum and broad spectrum UVA-UVB protection requires reapplication every 80 minutes during water activities or heavy sweating. Wide-brimmed hats with 3-inch minimum brims shade face and neck more effectively than baseball caps. Lightweight long-sleeve shirts with UPF 50 rating block 98 percent of UV radiation. Polarized sunglasses reduce glare from ocean and wet surfaces while protecting against cataracts and photokeratitis.
Insect repellent containing 20-30 percent DEET provides 4-6 hours of mosquito protection. Puerto Rico reported no locally transmitted Zika virus cases since 2017 according to Centers for Disease Control data through 2023. Dengue fever remains endemic with periodic outbreaks particularly during rainy season. Mosquito species Aedes aegypti that transmits dengue bites primarily during daytime hours. Repellent application to exposed skin and permethrin treatment on clothing create dual protection layers. El Yunque National Forest and coastal mangrove areas harbor higher mosquito populations than urban San Juan districts. Evening hours from dusk through dawn present increased exposure risk. Long pants and long sleeves treated with permethrin add protection during forest hikes and evening activities.
Waterproof phone cases or dry bags protect electronics during water activities and unexpected rain. The Río Camuy Cave Park maintains near 100 percent humidity inside cave chambers. Moisture condenses on camera lenses and phone screens within minutes of cave entry. Silica gel packets in camera bags absorb humidity but require periodic drying or replacement. Beach environments expose electronics to saltwater spray and sand. Waterproof cases rated IPX7 or higher withstand submersion in one meter of water for 30 minutes. Ziplock bags provide basic moisture protection for documents and paper currency.
Swimming attire follows United States mainland standards. Public beaches including Flamenco Beach and Luquillo Beach permit standard swimwear. Topless sunbathing remains culturally uncommon and draws attention. Old San Juan restaurants and shops enforce shirt and shoe requirements. Resort areas in San Juan including Condado and Isla Verde districts maintain casual dress codes during daytime but request long pants and collared shirts for evening dining at upscale establishments. Castillo San Felipe del Morro and Castillo San Cristóbal historic sites have no specific dress codes beyond basic public decency standards.
Cash remains important despite widespread credit card acceptance. Small colmado shops, beach vendors, and food kiosks in areas outside San Juan metro region operate cash-only. United States dollar serves as official currency eliminating foreign exchange requirements for US visitors. ATMs dispense US dollars with standard mainland banking network fees. Payment terminals accept chip-and-PIN and contactless payment methods common in United States retail environments.
Reusable water bottles reduce plastic waste and provide hydration access. Tap water throughout Puerto Rico meets United States Environmental Protection Agency standards and remains safe for consumption according to Puerto Rico Aqueduct and Sewer Authority. Some visitors prefer bottled water taste. Carrying filled bottles onto beaches and trails proves more convenient than purchasing from limited vendor locations. Insulated bottles maintain cold water temperature for 12-24 hours in tropical heat.
Daypack capacity between 15-25 liters accommodates daily essentials for hiking and beach outings. Internal pockets organize small items including sunscreen, snacks, and first aid supplies. External water bottle pockets provide quick hydration access. Padded shoulder straps distribute weight across shoulders during full-day excursions. El Yunque trails including El Toro peak at 3,533 feet elevation require 3-4 hours round trip with continuous moderate climbing. Adequate pack capacity carries required water volume of 2-3 liters per person plus rain gear and emergency supplies.
First aid kits should contain adhesive bandages, antibiotic ointment, pain relievers, anti-diarrheal medication, antihistamines, and any prescription medications. Pharmacies including Walgreens and CVS operate throughout San Juan and major municipalities following United States pharmaceutical regulations. Prescription transfers from mainland United States pharmacies process without complications. Visitors requiring specific medications should carry sufficient quantities for entire trip duration plus 3-5 day buffer for travel delays. Original prescription bottles with printed labels prevent customs questions and enable refills if necessary.
Snorkel and dive certifications from recognized agencies including PADI and SSI gain acceptance at Puerto Rico dive operators. Certification cards prove training levels for guided dives at sites near Culebra Island and Desecheo Island. Operators provide equipment rental but personal gear ensures familiarity and proper fit. Wetsuits rarely prove necessary in water temperatures between 78-82 degrees Fahrenheit year-round. Dive computers track depth and bottom time more accurately than dive watches. Underwater cameras capture reef scenes and marine life encounters. GoPro housings withstand depths to 33 feet without additional housing.