Thailand's islands and coastal provinces attract divers of every experience level. Most dives are completed safely, but unusual symptoms after surfacing must be taken seriously. Decompression illness is an umbrella term that includes decompression sickness, caused by gas bubbles in tissues or blood, and arterial gas embolism, which can follow lung overexpansion. Both can injure the brain, spinal cord, lungs and other organs.
Symptoms may begin soon after a dive or develop over several hours. They can look minor at first, and a dive computer showing no violation does not rule them out. The right response is oxygen, urgent specialist advice and medical evaluation, not waiting to see whether sleep fixes the problem.
Symptoms that should trigger action
Possible signs include unusual joint or muscle pain, tingling, numbness, weakness, dizziness, difficulty walking, poor coordination, severe fatigue, confusion, visual change, rash or marbled skin. Chest pain, coughing, breathlessness, collapse, loss of consciousness, bladder problems or paralysis are especially urgent. Sudden neurological symptoms within minutes of surfacing may indicate arterial gas embolism.
A mild ache after carrying cylinders can be musculoskeletal, and seasickness can cause nausea or fatigue. You cannot safely distinguish these from decompression illness through a checklist alone. Consider the timing, whether symptoms are new or out of proportion and whether they change. If there is doubt, contact emergency medical services and a diving-medicine specialist.
Do not dismiss symptoms because the dive was shallow, within tables or computer limits. Rapid ascent, omitted stops, repeated dives, exertion, cold, dehydration and individual physiology can affect risk, but cases can occur without an obvious error.
Stop diving and call for help
End diving for the day and do not re-enter the water to recompress. In-water recompression can lead to drowning, worsening symptoms, oxygen toxicity or an uncontrolled ascent and should not be attempted by recreational divers. Call Thailand's medical emergency number 1669 for serious symptoms and notify the dive operator. Ask for contact with the nearest facility experienced in diving medicine or hyperbaric treatment.
Give the location, symptoms, time of onset and whether the person is conscious and breathing normally. On an island or liveaboard, early coordination is essential because boat, road and air transfers take time. The Thailand emergency guide can help with location and communication, but the operator's emergency action plan should identify the local evacuation route.
A diving emergency assistance organisation may help coordinate specialist advice, yet it does not replace local emergency services. Do not delay the initial call while searching for insurance details or the ideal chamber. The closest hospital may need to stabilise the person before transfer.
Give high-concentration oxygen if trained and equipped
Administer the highest concentration of oxygen available using the dive operator's emergency kit, following training and device instructions. Oxygen can reduce inert-gas load and support injured tissues, but improvement does not prove the problem has resolved. Continue while awaiting professional guidance and during transfer if supplies and safety allow.
Check cylinder contents, remaining pressure and delivery equipment. Keep oxygen away from flames, cigarettes, oil and ignition sources. A trained provider should monitor breathing and be ready to start CPR if the person becomes unresponsive and stops breathing normally. Do not give oxygen in a way that delays evacuation.
If oxygen is unavailable, arrange urgent transport anyway. Do not substitute compressed air, nitrox or improvised gases. Do not place the person in a hot bath or sauna in an attempt to move bubbles; overheating and dehydration can complicate care.
Position, fluids and observation
Keep the person resting in a comfortable horizontal or recovery position as appropriate. There is no need for a head-down position, which can impair breathing and increase aspiration risk. If the person is fully awake, not vomiting and able to swallow, small amounts of non-alcoholic oral fluid may be reasonable while following medical advice. Do not force fluids and do not give anything by mouth to someone drowsy, confused or likely to need an urgent procedure.
Avoid alcohol, sedatives and strenuous movement. Record symptoms and their time of onset, but do not repeatedly test strength by making the person walk. Preserve warmth without overheating. Reassess consciousness and breathing frequently.
Even if pain or tingling disappears with oxygen, continue with medical evaluation. Symptoms can recur, and early recompression treatment is generally more effective than delayed care. A clinic that treats routine travel illness may not have the required expertise; how healthcare access works in Thailand explains the system, but ask specifically about emergency diving medicine.
Information to collect without delaying care
Bring the dive computer or written profile, including depths, bottom times, surface intervals, ascent rate, safety or decompression stops and breathing gas. Note all dives over the previous several days, not only the most recent one. Record the time of surfacing, symptom onset, oxygen administration and any changes.
Tell clinicians about previous decompression illness, lung or heart conditions, recent illness, medications, pregnancy possibility and any loss of consciousness underwater. If a rapid ascent followed equipment failure or breath-holding, say so clearly. The buddy's account may be important when the diver is confused.
Do not alter or delete the computer log. Do not spend time producing a perfect report before leaving. A photograph of the dive-computer screen and the operator's contact details are often enough to preserve information during transfer.
Flying after diving
Lower cabin pressure at altitude allows residual inert gas to expand, so flying too soon after diving raises risk. CDC guidance advises a minimum preflight surface interval of 12 hours after a single dive with no decompression stop, at least 18 hours after multiple dives in a day or several days of diving, and substantially longer after dives requiring decompression stops. Many conservative plans use 24 hours after repetitive recreational diving. Individual agencies may set stricter rules.
These intervals apply to divers who feel well. A person with possible decompression illness should not board a commercial flight or travel to altitude until evaluated and cleared by a diving-medicine professional. A normal flight schedule, expiring visa or prepaid connection does not make flying safe. Medical evacuation may require cabin-pressure planning and specialist coordination.
Altitude also matters on land. Driving over a high pass or taking an elevated route soon after diving can lower ambient pressure. Ask the operator whether the transfer to the airport or accommodation involves meaningful ascent.
Prevention before the boat leaves
Choose an operator that checks certification, explains the plan, maintains oxygen and communication equipment and has a written evacuation procedure. Ask where the nearest appropriate medical service is and how long transfer normally takes. A professional answer should include more than the name of a chamber, because chamber availability and suitability can change.
Stay within training and personal limits, make controlled ascents, complete required stops and monitor gas rather than relying only on a guide. Avoid diving when ill, congested, unusually fatigued or impaired by alcohol or drugs. Hydrate normally and protect against heat, but do not assume extra water cancels a risky profile.
Review travel timing before booking the last dive. The medical appointment checklist can help organise records after an event, and what to do when sick in Thailand covers practical support for a companion. Neither replaces a dive-specific emergency plan.
The essential rule is simple: new neurological, breathing, skin or disproportionate pain symptoms after diving deserve immediate expert contact. Stop diving, give oxygen if trained, call for help and do not fly. Acting early gives clinicians the best chance to assess and treat a problem that cannot be safely ruled out on the beach.
Frequently Asked Questions
Can decompression sickness happen after a dive within computer limits?
Yes. Tables and computers reduce risk but do not eliminate it. New pain, neurological symptoms, unusual fatigue, rash or breathing problems after a dive still require specialist advice.
Should I go back underwater to recompress?
No. Recreational in-water recompression can cause drowning, oxygen toxicity and further pressure injury. Stop diving, provide oxygen if trained and arrange urgent medical evaluation.
Can I fly if symptoms disappear after oxygen?
No. Improvement with oxygen does not mean decompression illness has resolved. Do not fly or travel to altitude until a diving-medicine professional has evaluated and cleared you.
How long should I wait to fly after an uncomplicated dive?
CDC guidance gives at least 12 hours after one no-decompression dive and at least 18 hours after multiple dives or several diving days, with longer waits after decompression dives. Follow the most conservative applicable guidance.
Sources
Writer
Niran Chaiyasit
Niran Chaiyasit is a Thai health writer with a background in public health and a focus on travel health, disease prevention and healthcare access in Thailand. His work covers topics such as common illnesses, vaccinations, mosquito-borne diseases, food safety and practical health information for travelers and expatriates.
Medical review
Justin Brooks
Daniel Brooks is an American health writer with a background in health sciences and a focus on rehabilitation, musculoskeletal health and patient education. He writes about physiotherapy, injury recovery, pain management, preventive health and practical healthcare guidance for international patients and travelers.
