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Travel Planning
Everything you need for beaches, water activities, jungle hikes, and the tropical climate
Verified 2026 · Island Seeker Editorial
quick answer
The most important items to pack for Guam are reef-safe sunscreen (required — regular sunscreen is harmful to Guam's protected coral reefs), a rash guard for snorkeling and water sports, water shoes or trail runners for hiking, lightweight rain gear, and a US Type A/B plug adapter if you're travelling from outside North America. US dollars are accepted everywhere — no currency conversion needed.
Plug type
US Type A / B (110V)
Currency
US Dollar (USD)
Climate
Hot & humid year-round
Sunscreen
Reef-safe only
Dress code
Casual tropical
Vaccinations
None required
Reef-safe sunscreen (SPF 30–50+): This is the most critical item. Guam's waters are a protected marine area — regular sunscreen containing oxybenzone and octinoxate damages coral reefs and is strongly discouraged. Pack mineral-based (zinc oxide or titanium dioxide) reef-safe sunscreen from home, as options in Guam can be limited and expensive.
Swimwear: Pack at least two sets — you'll be in the water daily and one set needs to dry while you wear the other. Rash guards are highly recommended for snorkeling and water sports, protecting against UV rays and sharp coral. UPF 50+ is ideal.
Sunglasses with UV protection and a wide-brim sun hat are essential. Guam's equatorial position means the sun is extremely intense — UV index regularly hits 11+ (extreme). Polarised sunglasses are especially useful on the water.
Guam's climate is hot and humid year-round — light, breathable clothing is all you need for most of the trip. Linen or moisture-wicking fabrics work best. Avoid heavy cotton which stays wet and heavy in humidity.
A lightweight waterproof jacket or packable rain poncho is useful year-round — afternoon rain showers can appear quickly even in the dry season. During the wet season (July–November), a more substantial rain layer is worthwhile.
Footwear: flip flops or sandals for beach and casual use; water shoes for reef walking and snorkeling (Guam's reefs and rocky shores are sharp); trail runners or hiking shoes if you plan to hike (sandals are not suitable for jungle trails with river crossings). Resort wear is acceptable at most restaurants — very few places require formal attire.
Guam uses US-standard electricity — Type A and B plugs at 110V/60Hz. If you are travelling from Japan (100V, Type A), your devices will work without an adapter. If travelling from South Korea, Taiwan, or most other countries (220–240V, Type C/F or others), you will need a US plug adapter. Modern phone chargers and laptop power supplies are typically dual-voltage (100–240V) and only need the plug adapter, not a voltage converter.
A waterproof phone case or dry bag is highly recommended for beach, boat, and water activity days. Guam's water and outdoor activities expose phones to significant moisture and spray.
Portable power bank: useful for long day trips into the south or north of the island where charging points are limited. Many tours and boat trips are full-day and your phone battery will be working hard with maps, photos, and translation apps.
No vaccinations are required for entry into Guam for most nationalities. The CDC recommends being up to date on routine vaccinations. Tap water in Guam is generally safe to drink (it meets US EPA standards), though some visitors prefer bottled water as a precaution.
Insect repellent: mosquitoes are present in Guam, particularly in jungle areas and after rain. Pack DEET-based or picaridin repellent for hiking and outdoor activities. Dengue fever has been reported in Guam — take mosquito precautions seriously.
Basic first aid kit: antiseptic cream, plasters, pain relief, antihistamines, and any personal medications. Guam has pharmacies but they can be expensive and may not stock unfamiliar brands. Bring any prescription medications in their original packaging with documentation.
questions & answers
Do I need reef-safe sunscreen in Guam?
Reef-safe sunscreen is strongly recommended — and effectively required for responsible snorkeling and swimming in Guam's marine areas. Guam's reefs are protected ecosystems and regular sunscreen chemicals (oxybenzone, octinoxate) cause coral bleaching. Mineral-based sunscreens (zinc oxide or titanium dioxide) are the reef-safe alternative. Pack from home — options in Guam are limited and more expensive than at major international airports or home countries.
What plug adapter do I need for Guam?
Guam uses US-standard Type A and B plugs at 110V/60Hz. US and Canadian travellers need no adapter. Japanese travellers (Type A, 100V) also need no adapter — devices will work. Korean, Taiwanese, and most other Asian and European travellers need a US Type A/B adapter. Most modern phone chargers and laptop power supplies are dual-voltage (100–240V), so only an adapter is needed — not a voltage converter.
What should I not pack for Guam?
Do not pack: regular (non-reef-safe) sunscreen for use in the ocean; fresh fruit, vegetables, or plants (prohibited by Guam Customs and Quarantine Agency — heavy fines apply); heavy winter clothing (Guam is tropical year-round); and formal dress attire (very rarely needed). Pack light — laundry services are available at most hotels.
Is tap water safe to drink in Guam?
Guam's tap water meets US EPA standards and is technically safe to drink. However, many visitors and locals prefer bottled water as a precaution, particularly as the water supply can occasionally be affected by typhoon damage to infrastructure. Bottled water is widely and cheaply available at convenience stores across the island.
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