Phuket Thailand

For most travelers, November to April is the most reliable window for Phuket scuba because sea state is calmer and visibility is more consistent. Expect warm water around 27°C to 30°C with many days in the 15 m to 30 m range when conditions line up. May to October is the southwest monsoon, which can mean rougher crossings and more cancellations, especially for exposed routes. If you travel in monsoon months, book flexible plans, keep extra buffer days, and prioritize sheltered island routes when operators run.

The Similan Islands operate with a defined seasonal closure. The official park schedule lists the park as open from October 15 to May 15 and closed from May 16 to October 14. If Similan is your main goal, choose travel dates inside that open window first, then build the rest of your Phuket plan around it. Even in the open season, offshore conditions can still change, so keep at least one buffer day for weather and confirm your operator's departure pier and transfer plan.

Day trips are best for nearby zones like Racha Yai, Shark Point, and sometimes Phi Phi. They work well if you want hotel comfort, flexibility, and shorter commitments. Liveaboards make the most sense when your wish list includes offshore parks like Similan and Surin or sites like Richelieu Rock, because they reduce long daily crossings and let you dive early and late. If you have 6 to 8 days total, a common pattern is 2 to 3 Phuket day trips plus a 3 to 5 night liveaboard block.

Thailand's Immigration Bureau provides the TDAC as an online form that replaces the traditional paper arrival card. The TDAC manual states all non-Thai nationals must submit the form online prior to entry, and that submission is required 3 days in advance of the arrival date. Plan to complete it before you travel, then keep the confirmation accessible (email or screenshot) for arrival. If your accommodation or flight details change, the manual notes you can update your submission before travel.

Fees depend on where you go. Offshore parks like Similan and Surin commonly charge an entry fee (often quoted around THB 500 for foreign adults, with reduced child rates), while Phi Phi day trips often include a separate national-park entry fee collected on arrival. Some Phi Phi diving itineraries also note an additional diver surcharge on top of general entry. Because operators vary in what they include, ask for a written breakdown at booking and bring cash as a backup even if you pay the tour by card.

Newer divers typically start at Koh Racha Yai because many sites are sheltered bays with sandy patches and straightforward navigation, often in the 5 m to 18 m range. These profiles are well suited for buoyancy practice, mask skills, and relaxed photo stops. Your operator can then step you up to pinnacles like Shark Point or Anemone Reef when you are comfortable with drifting and boat procedures. If you want to improve fast, schedule your first day as a skills-focused tune-up before deeper wreck dives.

In May to October, treat west-coast snorkeling as condition-dependent because surf and rip currents can build quickly. The safest approach is to pick smaller, more sheltered bays, go early in the day, and use a snorkel vest or flotation if you are not fully confident. Avoid snorkeling in breaking waves or near boat lanes, and stay inside marked swim zones when present. If the water looks murky or choppy, pivot to a topside plan like Old Town, a cooking class, or a spa day instead of forcing a water session.

Bangkok Hospital Phuket lists a Diving Medicine Center that provides Hyperbaric Oxygen Therapy (HBOT) services and notes a 24 hour on-call diving physician. Save the contact number (+66 7625 4425) before you start diving, and make sure your insurance covers hyperbaric treatment and evacuation. In an emergency, use Thailand's medical hotline (1669) for ambulance support, then coordinate with your operator and insurance provider. The best outcomes come from early recognition and fast, organized response rather than waiting to "see if it improves."

Most visitors are comfortable with a 3mm suit in Phuket because water temperature stays warm, often around 27°C to 30°C. If you get cold easily, plan long repetitive dive days, or will be on extended boat crossings with wind chill, a 5mm full suit can be worth the extra space. For snorkeling, a rashguard plus swim leggings can prevent sunburn and stings while keeping you cooler than a thicker wetsuit. Always pack reef-safe sunscreen and a hat for surface intervals.

Start with buoyancy: keep fins, gauges, and cameras off the reef and avoid kneeling on coral. Never feed fish or crowd turtles and sharks for photos. Choose operators that use mooring lines instead of anchoring on reefs, brief responsible behavior, and manage group sizes. On land and boats, reduce waste by carrying a reusable bottle and refusing single-use plastics when possible. Finally, respect national-park rules and seasonal closures, which exist to protect reefs during rougher monsoon conditions and reduce cumulative pressure during peak visitation.