Guam uses the United States dollar as its official currency. All prices display in USD, and U.S. coins and bills circulate as they do in the fifty states. Banks include Bank of Guam, Bank of Hawaii, and First Hawaiian Bank, with branches concentrated in Hagåtña, Tamuning, and Dededo. ATMs dispense dollars and operate under the same networks as mainland machines—Visa, Mastercard, Plus, Cirrus. Credit cards process identically to mainland transactions. Travelers from the United States carry no foreign exchange risk and face no conversion fees.
Antonio B. Won Pat International Airport sits in Tamuning, four kilometers northeast of Hagåtña. The airport code is GUM. United Airlines operates the majority of civilian flights, connecting Guam to Honolulu, Tokyo Narita, Manila, Seoul Incheon, and other Pacific hubs. Japan Airlines, Korean Air, Philippine Airlines, and Jeju Air maintain regional routes. The terminal replaced its predecessor in 1996 and expanded its concourse in 2018. Ground transportation includes taxis, rental cars from Avis, Budget, Hertz, and Dollar, and the Guam Regional Transit Authority bus system, which began operations in 2009 but runs limited routes unsuitable for most airport transfers. Hotel shuttles serve Tumon Bay properties. No passenger rail exists on Guam.
United States citizens enter Guam without a passport if arriving directly from a U.S. state or territory, though federal photo identification remains mandatory. Direct flights from Japan, South Korea, Taiwan, Hong Kong, and other Visa Waiver Program countries permit stays up to forty-five days without a visa under Guam-CNMI Visa Waiver Program rules established in 2009. This differs from the mainland U.S. ninety-day ESTA allowance. Citizens of the Philippines require a visa regardless of entry point. All other nationalities follow standard U.S. visa requirements. Customs and Border Protection officers staff the airport. Agriculture inspectors confiscate brown tree snake detection items and enforce strict quarantine on fruit, plants, and certain animal products due to Guam's isolated ecosystem. The brown tree snake, accidentally introduced after World War II, has eliminated most native bird species, and preventing its spread to Hawaii drives inspection rigor.
Mobile connectivity operates on U.S. standards. Domestic U.S. carriers—Verizon, AT&T, T-Mobile—treat Guam as domestic territory for most unlimited plans, though individual plan terms vary. GTA TeleGuam and IT&E provide local service. Cellular towers cover Hagåtña, Tamuning, Dededo, and major highways, but northern jungles near Ritidian Point and southern villages like Merizo experience gaps. Data speeds match typical U.S. 4G LTE performance in urban areas. Public wifi appears in hotels, malls like the Agana Shopping Center, and some government buildings. The Chamorro Village market in Hagåtña offers wifi during its Wednesday night market operations. Internet cafes exist but have declined since smartphone adoption rose in the 2010s.
Tap water meets U.S. Environmental Protection Agency standards and flows from the Guam Waterworks Authority. The Northern Guam Lens Aquifer supplies most drinking water through wells drilled into the limestone plateau. Hagåtña, Tamuning, Dededo, Yigo, and Mangilao receive treated aquifer water safe to drink from taps. Southern villages like Umatac and Inarajan rely partly on surface water reservoirs, where treatment quality varies and locals sometimes prefer bottled water. The Fena Valley Reservoir, built in 1951, supplies treated water to the naval base and surrounding areas. Boil-water advisories occur after typhoons damage infrastructure—Typhoon Mawar in May 2023 disrupted service for weeks. Hotels in Tumon Bay maintain independent filtration. Bottled water from Payless, Cost-U-Less, and 7-Eleven costs one to three dollars per gallon.
Electricity runs at 110 volts and 60 hertz, matching U.S. mainland standards. Outlets accept U.S. two-prong and three-prong plugs. The Guam Power Authority operates the grid from combustion turbines fueled by imported diesel and fuel oil—no coal, no natural gas, minimal solar despite ample sunlight. Power costs average twenty-five to thirty-five cents per kilowatt-hour, roughly triple the U.S. mainland average, driven by fuel import dependence and small-scale generation inefficiency. Outages occur during typhoons and occasionally during peak summer air conditioning load. Travelers from the United States need no adapters. Visitors from Europe, Asia, or other 220-240 volt regions require voltage converters for devices lacking dual-voltage capability, plus plug adapters for U.S.-style outlets.