Health & safety
Guam Health and Safety: Reefs, Typhoons and a Snake
Guam is an easy island to be well in: English everywhere, two hospitals with round-the-clock emergency departments, and a resort area built for visitors. The precautions that matter are the island's own — the reef line and its currents, a long storm season, and one invasive snake with a bigger reputation than bite.
Updated 2026-09-19
The reef line and its currents
Much of Guam's shore is wrapped in reef, and the danger lies where the calm water inside meets the open ocean. Rip currents are powerful channels of water running quickly away from shore, strong enough to carry even good swimmers into deep water, and the island's emergency managers regularly warn inexperienced swimmers to stay out of the water altogether and to keep away from the reef line — especially along east-facing reefs — when surf and rip-current advisories are in force.
The everyday rules follow from that: never swim alone, swim where lifeguards, flags and signs tell you to, stay close to shore and inside the reef, and keep away from the cuts where water drains out through it. If a current does pull you out, swim parallel to the shore rather than straight against it, then head back in. Some beaches, including the refuge beach at Ritidian, have no lifeguard on duty, and the refuge asks swimmers to use a flotation device.
Typhoon season
Typhoons can reach Guam in any month, but the main season runs from July to November, with its peak from mid-August to mid-September, and it overlaps the rainy season of roughly July to November. A trip in those months is still very possible; it simply calls for flexible bookings, travel insurance that covers weather disruption, and an eye on the forecasts and advisories issued by the National Weather Service in Guam and the island's Office of Civil Defense, whose instructions come first if a storm approaches.
The brown treesnake
The brown treesnake is an invasive species on Guam, and it has eliminated most of the island's native forest birds. For people it is a nuisance rather than a danger: the snake is mildly venomous but not considered dangerous to adults, although young children can react to a bite, so leave any snake alone. Keeping it from spreading to other islands is taken seriously, with cargo inspections at the airport and the commercial port, so check your luggage before you pack up to leave.
Hospitals, sun and restricted land
Guam Memorial Hospital in Tamuning, the island's public hospital, and Guam Regional Medical City in Dededo both run emergency departments around the clock. The tropical sun is strong all year, so sun protection matters as much in the dry season as at any time, and a reef-safe sunscreen helps protect the reefs you came to see. Large areas of the island are military installations, fenced and closed to the public; respect the signs and boundaries, including on beaches that lie inside them.