Scuba Diving at Siam Bay, Racha Yai

Diving at Siam Bay, Racha Yai (Thailand)

Descending into Siam Bay on Racha Yai offers a welcoming introduction to diving for beginners and a relaxed exploration for experienced divers. This site provides an easy entry into Andaman Sea conditions, with generally calm waters ideal for practicing skills or simply enjoying the underwater scenery. Divers will appreciate the unique blend of natural reef patches and intriguing man-made monuments, creating a distinctive experience within Racha Yai’s northernmost bay.

Tonight's objective overview for Siam Bay, Racha Yai shows an air temperature of 29.5°C. The measured surface conditions include wave heights around 1.5 m. This environmental data is logged for the close of the day.

Dive Site Location & Key Facts

Coordinates7.6178, 98.3702
Site Characteristics
OceanSandy Bottom
Max Depth20m / 66ft
Entry Typeboat
Water Typesalt
Dive Types
Reef

Dive Site Overview

Siam Bay, the northernmost cove of Racha Yai, presents a varied underwater landscape blending natural reef elements with distinct artificial attractions. Its perimeter is characterized by rocky edges, gradually transitioning towards a predominantly sandy center interspersed with patches of hard coral.

A notable feature rests between 18 and 20 m / 59 and 66 ft: a collection of man-made monuments. These include two elephant statues and a large temple gate, guarded by a mythical giant sentry, a 'Yak,' believed to deter malevolent spirits.

These statues serve as a potential drop point for dives, guiding exploration along the seabed. A journey to Racha Yai from Chalong Bay typically takes about 1 hour 20 minutes, offering time for preparation before the first descent.

While beginners find ample shallow areas to navigate, more experienced divers can easily descend directly to these deeper reef sections, down to around 20 meters. The overall depth range at Racha Yai is reported to be between 5-30 m / 16-100 ft, though conditions for deeper dives might vary by specific bay and skill level.

Sandy expanses and coral patches at the site create diverse habitats, offering opportunities for discovery across different depth contours. It’s an environment suitable for a range of certification levels, from introductory dives to advanced explorations.

Siam Bay, Racha Yai

Conditions are Poor

4/10
Confidence: 8/10
Indicates meteorological model agreement and data availability.
DIVE WARNING

High Wind Advisory (41km/h). Unsafe surface.

06:12
18:45
H: 10:45
L: 16:20
Air / Sea Temp
29° / 31°
Wave Height
1.6 m
Wind Speed
41 km/h WSW
Rain Chance
100%

Current conditions near Siam Bay, Racha Yai show 29° air, 31° sea temperature, 1.6 m waves, and 41 km/h wind. Forecast data is refreshed regularly to ensure accuracy.

Radius: ~12km
Updated: Aug 4, 2026, 20:34 local time
MARINE: OPEN-METEOWEATHER: YR.NO

Best Time to Dive

Visibility is often a primary consideration for divers, and Siam Bay generally offers very good underwater clarity, frequently averaging 20 meters and ranging from 15-30 meters. Consistent visibility, coupled with the sheltered nature of Racha Yai's bays, allows for diving opportunities year-round. However, certain periods provide more optimal surface and underwater conditions. From January to March, the dry season typically sees minimal rainfall, often less than 1.5mm, and stable air temperatures around 27-28°C. This period is associated with high dive scores, suggesting favorable overall conditions. While rainfall increases between June and September, often peaking around 9.7mm, the site remains accessible, though surface conditions might be choppier with average wave heights increasing to over 1 meter. For clearer skies and calmer seas, targeting the drier months generally provides the most comfortable experience above and below the surface.

PEAK SEASON SCORE

85/100
Very Good

Scores combine air & water temps, waves, wind & rainfall for overall conditions.


BEST MONTHS TO DIVE

FEB
MAR
DEC
DIVE SCORE
(0–100)
83
JAN
85
FEB
88
MAR
82
APR
74
MAY
73
JUN
73
JUL
75
AUG
70
SEP
81
OCT
81
NOV
84
DEC
AIR TEMP (°C)
28
28
29
29
29
29
29
28
28
28
28
28
WATER TEMP (°C)
29
29
30
31
31
30
30
30
29
30
30
29
WAVES (M)
0.7
0.7
0.5
0.5
0.9
1.2
1.3
1.1
1.3
0.8
0.7
0.6
WIND (KM/H)
29
28
26
23
24
27
28
27
30
23
26
27
RAIN (MM)
1.0
1.2
1.5
4.7
8.3
6.7
5.9
7.8
9.8
9.2
9.4
4.5
DIVE SCORE GUIDE (0–100)
Excellent (90–100)
Very Good (80–89)
Good (70–79)
Moderate (50–69)
Poor (30–49)
Not Recommended (0–29)

Monthly records compiled from satellite and marine observation nodes over the last 3 years. Data provided by Open-Meteo and MET Norway.

Dive Experience & Conditions

Starting a dive at Siam Bay often involves a calm descent, particularly for new divers utilizing the shallow areas for skill development. As you progress, the environment remains quite manageable, with easy diving conditions making it a popular choice for introductory experiences and certification courses. Expect generally mild currents, which contribute to a relaxed underwater exploration. Water temperatures typically range from 27-29°C / 81-84°F, providing a comfortable diving environment without the need for thick wetsuits. Its structure, featuring sandy expanses transitioning to hard coral patches and rocky sections, offers varied points of interest throughout a single dive. Navigation around the man-made monuments between 18-20 meters adds a unique element to the dive, guiding divers through a distinctly arranged underwater setting. Overall, the feel is one of accessibility and gentle discovery, suitable for refining techniques or simply enjoying the tranquil depths.

Dive Difficulty & Safety Guidelines

Prioritizing safety at Siam Bay means being aware of your dive plan and adhering to your certification level. Although conditions are generally calm and easy, maintaining the buddy system and regular depth and air checks are fundamental. Its suitability for beginners means it's often visited by divers undergoing instruction, so exercise awareness regarding other groups and their training activities.

There are no specific hazards commonly reported for Siam Bay beyond standard dive considerations. Racha Yai trips accommodate all diver levels, from Discover Scuba participants to more experienced individuals, so be mindful of varied skill sets underwater.

Always ensure your equipment is well-maintained and consider a dive computer for precise depth and no-decompression limit monitoring. A responsible approach ensures a safe and enjoyable experience for everyone.

Recommended Equipment

  • Dive Computer
  • DSMB

This gear list is based on verified equipment signals for Siam Bay, Racha Yai, Thailand. Always confirm final gear choices with your dive operator, guide, or liveaboard.

Recommended Dive Suit

Individual comfort in the water can vary significantly from diver to diver, even under the same conditions.

For most recreational dives, dive skin or rash guard should provide comfortable protection. Consider warmer surface protection (like a boat coat) due to brisk winds. Forecast trends indicate little change in overall diving conditions during the next few days.

Current temperature readings suggest that the water at Siam Bay, Racha Yai is around 31°C (87°F). Surface air temperatures are resting at 29°C (85°F).

Siam Bay, Racha Yai conditions last reviewed: 20:34 local time (UTC+7), Aug 4, 2026

Emergency & Medical Support

Essential information to help you plan your dive trip to Siam Bay, Racha Yai.

Hyperbaric Chamber

Hyperbaric chambers are a critical part of dive safety infrastructure. Availability varies significantly by region, and not all dive areas have immediate access.

Before diving, it's recommended to:

  • confirm nearest medical facilities
  • check emergency procedures with local dive operators
  • ensure dive insurance covers evacuation if required
24/7 Available

Divers Alert Network

Diving emergency assistance available through DAN World.

+1-919-684-9111
  • 24/7 emergency hotline
  • Diving medical assistance
  • Evacuation coordination
View official DAN emergency contacts

Emergency contacts are provided for reference. Always verify local emergency services before diving.

Marine Life at Siam Bay, Racha Yai

Siam Bay's varied underwater landscape supports a range of marine life, particularly thriving in its sandy expanses and hard coral patches. Sandy areas are prime spots to observe Kuhl’s Stingrays, often found hiding, sometimes alongside peacock flounders.

Within the coral formations and rocky edges, divers commonly encounter moray eels, lionfish, and scorpionfish taking shelter. Smaller reef residents like damselfish are abundant, and garden eels can be spotted swaying in sandy areas.

Occasional sightings of small barracudas, parrotfish, and batfish add to the activity. While less common, ghost pipefish and stonefish are also among the rarer visitors, often blending seamlessly into the environment.

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Dive Centers Near Siam Bay, Racha Yai

Nava Scuba Diving
20 km away
5| 731 reviews
Rumblefish Adventure
4.8| 156 reviews
24.1 km
Tommy'S Divecenter Phuket
4.8| 100 reviews
19.3 km
Love Diving Phuket
4.9| 1537 reviews
31.7 km
Phi Phi Cabana Diving
Phi Phi Cabana Diving
4.9(438)• 46.5 km
PKT  Diving Co. Ltd
PKT Diving Co. Ltd
No reviews• 46 km

Nearest Airports

Nearest airports to help plan travel to this dive area.

Phuket International AirportHKT
55 km
Krabi International AirportKBV
86 km
Trang AirportTST
138 km
💵Currency:THB

Search Flights

Check available flights and routes on Expedia, using the nearby airports listed in this section.

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Frequently Asked Questions

Is Siam Bay a good dive site for new divers?

Yes, it's frequently used for beginner courses and Discover Scuba Diving trips due to its calm, easy conditions and plenty of shallow areas. The environment is forgiving for those developing their skills.

What unique features can I find underwater at Siam Bay?

The bay is home to several man-made monuments, including two elephant statues and a large temple gate guarded by a mythical giant sentry, or Yak. These distinctive features are situated at depths between 18 and 20 meters.

What is the typical visibility at this site?

Divers can generally expect good visibility, averaging around 20 meters. It can range from 15 to 30 meters depending on specific conditions.

What kind of marine life might I encounter?

The sandy bottom is a good place to spot Kuhl's Stingrays and peacock flounders. Look for moray eels, lionfish, and various reef fish like damselfish near the coral patches.

What are the average water temperatures for diving here?

Water temperatures are comfortably warm throughout the year, typically ranging between 27-29°C / 81-84°F. This usually means only light thermal protection is needed.

How long is the boat journey to Racha Yai from Phuket?

A typical boat trip from Chalong Bay, Phuket, to Racha Yai takes approximately 1 hour and 20 minutes. This allows for ample time to prepare before your first dive.

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