The Tunnel

Best time to dive

January to December; September to December; December to April

What you might see

• BarracudaLikely
• Eagle rayLikely
• Grey reef sharkLikely
• Hammerhead sharkPossible
• Moray eelLikely
• Sea turtleLikely
• Whale sharkLikely

Sightings are seasonal probabilities, not promises - even in peak season nature does its own thing.

Certification & difficulty

Advanced Open Water - advanced conditions (currents/depth); dive within your training.

Snorkelling

Not a snorkel site - No - overhead dive

Safety notes

Naval Base Guam runs the region's only recompression chamber (the busiest US Navy chamber in the Pacific), a notable safety plus; otherwise standard tropical boat/shore-diving precautions; overhead environment - use a light and stay with the guide

Permits & fees

No dive permit or fee for most sites; Guam's marine preserves (incl. Piti Bomb Holes and Tumon Bay) are no-take; some Apra Harbor/Orote sites lie within Naval Base Guam and need base access or a base-affiliated operator

Permits and operators change - confirm before booking.

Location

Nearest hub: Guam