divehappy.com · Editorial
Editorial guide for exposure, lower itinerary frequency and trip timing.
Dive Spot Guide•
Boulder City
Boulder City, Thailand is a boat-only Similan boulder dive.
Local operator required
Boat-only Similan access and mooring-line descents make operator support necessary.
Boulder City, Thailand is a mooring-line Similan site with strong current, deep boulders and a route that rewards careful timing.
About Boulder City
Boulder City, Thailand is a boat-only Similan dive of huge granite pinnacles, corridors and sand lanes that feel like an underwater city. It suits divers who are comfortable with mooring-line entries, depth discipline and current-aware route planning, with the best dives happening when the water is calm enough to work the boulders rather than fight the site.
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Research Estimate At Boulder City
Conservative baseline from public research. No community dives logged yet.
VisibilityVisibility: 20m
AccessModerate entry effort
CoralMixed health
Aquatic LifeExceptional variety
FacilitiesBasic facilities
Crowd / PopularityFew visitors
CurrentStrong current
SurgeStrong surge
Where Is Boulder City?
This spotNearby spotsExplore nearby spots on the map
Community sourced coordinates.
Boulder City Planning Details
Depth range, seasonality, and planning context.
Reported Depth
12m - 40m
Depth Note
Shallowest boulders sit around 12-14m; deeper sand and rock reach about 40m, with a mooring line around 18m.
Best Season
December to April
Typical Conditions
Exposed deep boulder site with strong current, mooring-line descents and better days when the sea is calm.
Safety & Access At Boulder City
Hazards, restrictions, and access requirements.
Key Hazards
Strong currentSurgeWaves
Safety Notes
Use the mooring line when it is available, keep an eye on depth in the sand gaps and stay conservative if current builds.
Access Restrictions
Boat-only in the Similan Islands National Park; access depends on operator timing and the seasonal park opening.
Legal Notes
The site sits inside Similan Islands National Park, so seasonal opening and park rules apply.
Local Intel For Boulder City
Community notes to help plan your visit.
Scuba Diving
A deep scuba dive that can be run as an S-pattern around the main pinnacles, with mooring-line access and room to tuck behind the rocks when current builds.
Freediving
Not suitable as a freedive target because it is deep, exposed and boat-managed.
Snorkeling
Not a snorkel site; the terrain and depth make it a scuba dive.
Wildlife at Boulder City
Species commonly reported at this site, with direct links into their wildlife guides.
Recent Logged Visits At Boulder City
Community dive logs and visit reports for this site.
Dive Spot Log Averages At Boulder City
Average conditions based on logged dives & visits.
Conditions
Avg. Visibility20m
Activity
No dive activity logged yet.
