My friend and I are back packing throughout Thailand this July and August. We would like to go scuba diving off the east coast in Phuket/Ko Lanta or the west coast in Ko Tao. It is rainy season for both places but we had heard that Ko Tao always has some sheltered sites. We are interested in day trips. I love these forums and was hoping one of my fellow Fodorites could help me out!

Can anyone give us a more accurate description of what the weather/diving will be like in either of these places in late July?

July and August are definitely the rainy season on the west coast of Thailand which includes Phuket/Phi Phi/Koh Lanta. However, it is much less rainy on the east coast of Thailand, the whole Gulf of Thailand area which includes Koh Tao. I'm not a diver, so I can't vouch for the clarity of the water in the Gulf of Thailand at that time of the year.

Do you know about www.weatherbase.com which is an excellent resource for weather data.

With regard to water clarity, rain makes no difference in most offshore areas. For instance in the Similans, the water is actually more clear during the summer months; the islands are too far offshore to be affected by freshwater run-off.

Diving is usually equally good in the summer months, but it may be a good idea to carry some rain gear like a poncho for transportation between the boat and the car.

Ko Tao would be a good choice. Diving is best on the east side of the island where it is flat calm, crystal clear & teeming with marine life. A good season for turtles too.

Thank you both. Kathie, I have loved reading your Thailand trip reports and responses to others throughout my Thailand research.

We hear goog things about diving in both locations. I am worried about the commericialism of Phuket so I think we might try Ko Tao.

The Similans marine national park is closed for July and August every year because of rough seas and unpredictable weather. No diveboat company offer diving at the Similans for July and August either. You might get lucky and find some one who will take you to the closer islands like Racha Yai or Racha Noi if the sea is not too rough.

By the way the Thai summer months are from March - April so I'm not sure what country Legih is talking about with summer in July - August?

If you want to dive during July and August than stick to Koh Tao or areas with diving close to shore because of the normally rough seas during this time of year. The best diving in Thailand are around the Similans and Burma banks and the depth will be around 40 meters but definitely not during July and August. Best time of year for weather, sea condition and water clarity is the period from December to February IMO.

Thanks for the confirmation, Hanuman. It was my understanding that the monsoon season in Phuket involves not just rain but rough seas.

Kathie,

I've gone fishing(trolling) around the Racha islands during July and it was not comfortable. 6 - 10 foot seas with strong wind and white crested waves everywhere. You can find days with relatively calm winds and "small" seas but those don't happened too often.

My brother is an advance open water diver and he says that there are a few dive boats that would venture out to the Similans during July and August but they will be fined by the Thai park services for their "adventurism".

Certaily July/August Koh Tao would be your best choice.
If you are backpacking you can hop down the coast south of Bangkok.
You can go straight through to Koh Tao with Lomparyah from Bangkok, daytime and overnight, about US$28 each way. That is the bus to Chumphon and then the ferry.
You can also stop along the way down the coast, Bang Saphan and Koh Talu for snorkeling on the way. These are quiet places but you can find relatively cheap nice place to stay.
You can also train down the coast to Chumphon and take the ferry.
Once on Koh Tao you can go across to Koh Phangan or to Samui if you want, monitor the weather and if there appears to be a good spell of weather then easy enough to ferry to Surat Thani and take the bus to Krabi

This shows the coastal route:
http://www.lomprayah.com/E/route.htm