What Counts as a Pre-Existing Condition for Health Insurance in Thailand

Wondering what actually counts as a pre-existing condition in Thailand? Here’s what nine insurers’ own written policies say, quoted and translated, so you know before you apply.

Ask ten expats what “pre-existing condition” means and you’ll get ten different half-right answers. Some think it only counts if a doctor formally diagnosed you. Some think a fully healed injury from years ago doesn’t matter anymore. Some think it has to be something serious, not a minor issue you never got checked.

The actual answer lives in the fine print of each insurer’s policy wording, and it’s more specific, and in places stricter, than most people assume. So instead of guessing, I pulled the actual policy documents from nine insurers active in Thailand and read exactly how each one defines it.

Every claim below is backed by a direct quote from that insurer’s own written policy, application form, or product page, not a summary or a broker’s paraphrase. Two of them only publish their terms in Thai, so we translated those ourselves and marked them clearly.

We’re not a broker. This article explains what each insurer’s written policy says, sourced and quoted directly. It isn’t advice for your specific medical history. Talk to a licensed insurance broker or the insurer’s own underwriting team about your situation before you buy, switch, or declare anything on an application.

What Generally Counts as a Pre-Existing Condition

Before the quote-by-quote breakdown below, here’s the short version. The exact wording differs by insurer, but these patterns hold across almost every policy we read.

• Anything you were diagnosed with, treated for, or already knew about before your policy started, even if you never actually saw a doctor for it.
• Congenital and genetic conditions, usually as their own category, separate from the everyday sense of “pre-existing.”
• Chronic conditions that need ongoing management, like diabetes or high blood pressure, almost always excluded outright rather than reviewed case by case.
• Whether something that’s since fully healed still counts depends entirely on the insurer’s exact wording. Don’t assume either way.
• Most individual plans look at your whole medical history with no cutoff date. Employer or group plans sometimes only look back a fixed window, like 90 days.
• What you don’t disclose is treated the same as, or worse than, a condition you can’t get covered. Being upfront tends to produce a better outcome than hoping something goes unnoticed.

How Each Insurer’s Policy Actually Defines It

Five questions cover almost every gray area readers ask us about. For each one, here’s what the actual policy wording says, not a summary of it.

Something you were diagnosed with or treated for

This is the one part every insurer agrees on. If you saw a doctor for it, got a diagnosis, or received treatment before your policy started, it counts.

“Pre-existing condition – any disease, illness or injury, or symptoms present before the initial start date linked to such disease, illness or injury for which: medical advice or treatment has been sought or received…”

Cigna Global, Close Care Policy Rules, Sept 2024

“Chronic diseases, injury or sickness (including complications), conditions or abnormalities that have occurred before entering into the insurance contract (Pre-existing Condition).”

Allianz Ayudhya, Superior Health Plus policy summary

“Chronic disease, illness or injury or pre-existing illness conditions that the insured or dependant has been treated, diagnosed, consulted for or prescribed with medicine during a period of 90 days prior to the date of contract…”

Muang Thai Life Assurance, Group Insurance Benefits Manual

Notice that Muang Thai’s version only looks back 90 days for larger group policies. That’s the exception, not the rule. Individual plans generally don’t put a time limit on how far back they look.

Something you knew about but never saw a doctor for

This is where people get caught out. “I never got it officially checked” isn’t the safety net most readers assume it is, at least not with Cigna Global.

“…or the beneficiary knew about and did not seek medical advice or treatment.”

Cigna Global, Close Care Policy Rules, Sept 2024

That clause sits directly inside Cigna’s own definition of “pre-existing condition,” not a separate exclusion. Simply being aware of a symptom and choosing not to act on it is enough for it to count, in writing, under this specific policy.

Congenital and genetic conditions

Conditions present since birth get treated as their own category, separate from “pre-existing” in the everyday sense, and in at least one policy, it doesn’t matter whether anyone ever knew about it.

“Congenital conditions whether or not manifest and/or diagnosed or known about at birth unless allowed for by the benefits table and accepted by the Company in writing.”

AXA SwitchCare, Individual Health and Accident Insurance Policy Wording, Section 3 (General Exclusions)

“Pre-existing conditions, Congenital abnormalities, growth development abnormalities, and genetic disorders.”

Navakij Insurance, Long Stay Visa (Non-O-A) Table of Benefits

The AXA wording is the clearest on this point. “Whether or not manifest and/or diagnosed or known about at birth” means a congenital condition can be excluded even if neither you nor anyone else ever knew it existed until years later. Diagnosis timing doesn’t reset the clock.

A condition that’s since fully healed

Here’s a genuine point where insurers disagree, based on their own wording, not our interpretation of it.

Thai: “โรคที่เป็นมาก่อนกำเนิด โรคเรื้อรัง การบาดเจ็บหรือการเจ็บป่วยที่ยังมิได้รับการรักษาให้หายก่อนทำสัญญาประกันภัย”
English (our translation): “Congenital conditions, chronic diseases, and injuries or illnesses that had not yet been fully treated before the insurance contract was made.”

Viriyah Insurance, V Prestige Care product page

Viriyah’s wording only excludes injuries and illnesses that were still unresolved when the policy started. A broken arm that had already fully healed sits outside that specific clause, at least as written (congenital conditions and chronic diseases are still excluded regardless).

“The Company will not pay benefits under this Policy for any Pre-existing condition or Chronic Conditions, including any complications that are not yet fully cured before the date this Policy first comes into effect…”

AXA SwitchCare, Individual Health and Accident Insurance Policy Wording

AXA’s wording carries the same “not yet cured” qualifier. Compare that against Cigna and Allianz Ayudhya above, where the test is simply whether the condition existed or you sought treatment before the start date, with no exception written in for something that’s since resolved. Don’t assume “it’s fully healed now” protects you across every insurer. Confirm it against the specific policy wording, in writing, before you rely on it.

That’s a broker’s real-world read across the wider market, not specific to any one insurer here. Treat it as a general caution even where a policy’s own wording, like Viriyah’s or AXA’s above, seems to leave room for an exception.

Disclosure changes what happens next

One insurer, Dhipaya, doesn’t define pre-existing conditions with a fixed list at all. Instead, whatever you declare becomes the definition, condition by condition.

Thai: “เป็นที่ตกลงกันระหว่างผู้ขอเอาประกันภัยและบริษัทว่ากรมธรรม์ประกันภัยนี้จะไม่ให้ความคุ้มครองแก่ผู้ขอเอาประกันภัยสำหรับการบาดเจ็บหรือการป่วยซึ่งเกิดขึ้นโดยตรง หรือสืบเนื่องมาจาก หรือเป็นอาการแทรกซ้อนของการบาดเจ็บหรือการป่วยใดๆ ที่ผู้ขอเอาประกันภัยได้แถลงไว้ในใบคำขอเอาประกันภัยนี้ หรือที่บริษัทยกเว้นตามที่ได้ระบุในเอกสารแนบท้ายยกเว้นความคุ้มครองเฉพาะโรค… (โดยบริษัทจะออกเอกสารแนบท้ายยกเว้นความคุ้มครองเฉพาะโรคนั้นๆ เป็นการเฉพาะ)”
English (our translation): “It is agreed between the applicant and the Company that this policy will not cover the applicant for injury or illness arising directly from, resulting from, or as a complication of, any injury or illness the applicant declared on this application, or that the Company excludes as specified in an attached rider excluding coverage for that specific condition… (the Company will issue a rider excluding coverage for that particular condition individually).”

Dhipaya Insurance, TIP Health Care 20000 application document

Under this structure, an old, minor, unrelated condition you declare honestly might get its own narrow rider rather than triggering a broad exclusion. But it cuts both ways. AXA’s general exclusions carry a similar warning:

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“A Pre-existing Condition, disease, Injury, or Illness including any Associated Medical Conditions or complications or consequential conditions arising therefrom and conditions which were not disclosed to the Company before the date of the insurance agreement.”

AXA SwitchCare, Individual Health and Accident Insurance Policy Wording, Section 3 (General Exclusions)

Whatever you don’t disclose sits in the same exclusion bucket as a diagnosed pre-existing condition. Full, honest disclosure isn’t just good practice. It’s what several of these policies are written around.

Once a Condition Is Flagged, Here’s What Happens

Knowing something counts as pre-existing is only half the picture. What the insurer actually does about it varies more than most people expect. Four different approaches show up across these nine policies.

Flat exclusion, no path back

Navakij’s Long Stay Visa plan, built specifically for the O-A retirement visa, states it plainly:

“Pre-existing conditioned and chronic disease or illness and HIV, AIDS and Virus spreading are not covered under the above plan.”

Navakij Insurance, Long Stay Visa (Non-O-A) Table of Benefits

No moratorium, no written-agreement option, nothing that leads to coverage later. Viriyah’s V Prestige Care and Luma Long Stay Care (reviewed here) land in the same place, just with softer wording: “may be excluded from coverage.”

In practice, treat all three the same way. If it’s flagged, assume it stays uncovered.

Covered only with written agreement

Cigna Global’s Close Care plan (reviewed here) leaves the door open, but only if the insurer opens it first, in writing:

“We will not pay for treatment for a pre-existing condition of which the policyholder was (or should reasonably have been) aware at the date cover commenced, and in respect of which we have not expressly agreed to provide cover.”

Cigna Global, Close Care Policy Rules, Sept 2024

Whether that happens depends entirely on your medical questionnaire and their underwriting decision, not on anything guaranteed in the base policy. This is exactly why brokers push people to disclose everything rather than hope a minor issue goes unnoticed.

Covered automatically after a set period

AXA SwitchCare and Pacific Cross’s Expat Care both build a timeline into the policy itself, rather than leaving it to a case-by-case decision.

“…this Policy has been in effect for a continuous period of at least three (3) years, and the Chronic Conditions, Injury, or Illness… has not appeared, or has not been treated, or diagnosed by a Physician… during five (5) years before the date this Policy first comes into effect.”

AXA SwitchCare, Individual Health and Accident Insurance Policy Wording

In plain terms: if you honestly didn’t need medical attention for something in the 5 years before you applied, and you stay on the policy continuously for 3 years without it flaring up, AXA’s own wording treats it as no longer pre-existing.

Pacific Cross takes a shorter, capped approach. Its benefit table carries its own line item, “Pre-existing Conditions Coverage (2-year moratorium period),” separate from general coverage: THB200,000 on the entry-level Expat Care 1 plan, THB300,000 on Expat Care 2 and 3. Two years claim-free on a condition and it becomes covered up to that limit, the only one of these nine insurers that attaches a specific number to actually treating a flagged condition rather than just defining when it’s excluded.

Carved out condition by condition

Dhipaya’s TIP Health Care 20000 works differently from everything above, as shown in the disclosure quote earlier in this article. Rather than one blanket clause, each declared condition gets its own individual rider, while the rest of the policy stays intact. We’ve reviewed Dhipaya’s plans in more detail here, and Viriyah’s in more detail here.

If your employer offers group cover

Muang Thai’s Group Health Plus is underwritten differently again, through an employer rather than individual medical assessment. Its look-back window is 90 days for larger groups, and even a flagged condition clears automatically after 12 straight months on the plan, a much shorter path back to coverage than any individually-underwritten plan here. We’ve reviewed Muang Thai’s plans in more detail here.

One caveat: this wording is from their group product sold through employers. Their individually-purchased retail plans may be underwritten differently, so confirm which one you’re actually being offered, in writing, before assuming the same terms apply.

If No Insurer Will Cover You

If your condition gets you declined or excluded everywhere, you still have real options in Thailand. They’re just not private insurance.

• Thai Social Security (Section 33). If you’re legally employed in Thailand on a work permit, your employer registers you with the Social Security Office automatically, and it doesn’t carry the same pre-existing condition exclusions private insurers do. It’s not unlimited or five-star, but it’s real, usable coverage that doesn’t care what you had before you enrolled. We compare it against private options in our SSO vs. private insurance guide.
• The 30-baht scheme isn’t an option. Thailand’s Universal Coverage Scheme is for Thai nationals only. Being on a retirement visa, having a work permit, or even holding a residence certificate doesn’t get you into it. Skip this one; it’s not a real fallback for foreigners.
• The LTR’s bank-deposit alternative. If insurance is genuinely out of reach because of your medical history, the LTR visa itself offers a way around needing insurance at all: maintain a minimum of US$100,000 in a Thai bank account under your name for at least 12 months, per the official BOI requirement, and that satisfies the visa’s health coverage condition entirely. It’s a high bar, but it removes underwriting from the equation completely.
• Self-pay, with eyes open. Private hospital costs in Thailand for common chronic conditions like heart disease, diabetes, and cancer are lower than in the US or much of Europe, but they’re not nothing. Budget for it honestly rather than assume a declined application means you can’t retire here.

For the general mechanics of pre-existing conditions beyond Thailand specifically, including how moratorium underwriting differs from full medical underwriting and why disclosure matters so much, our sister site ExpatDen interviewed a broker with 20+ years underwriting these policies. He also confirmed something worth carrying into everything above. The country you live in doesn’t affect whether an insurer covers you. Only the policy wording does.

We’ve also spoken with the same broker, Carsten Creutzburg, about Thailand-specific coverage on our health insurance pillar page. You can read our full review of his brokerage here if you’d rather have someone review your specific medical history than compare policy wording yourself.

FAQ

Does a fully healed old injury count as a pre-existing condition?

It depends on the insurer’s exact wording. Viriyah and AXA’s policies specifically exclude conditions “not yet fully treated” or “not yet fully cured,” which suggests something genuinely resolved may fall outside that clause.

Cigna and Allianz Ayudhya’s wording doesn’t carry that exception; their language covers anything that “occurred before” or was “present before” the start date, regardless of current status. Confirm in writing with the specific insurer before assuming either way.

Does a pre-existing condition disqualify me from a Thai retirement visa?

No. The visa requires a minimum coverage amount, not proof that every condition is covered. You can hold a policy that satisfies the visa requirement while your specific condition sits excluded inside it. The two are separate questions.

Can I switch insurers later if my condition gets excluded now?

Generally no, and it can make things worse. A new insurer treats anything you developed or were treated for under your previous policy as pre-existing too, and switching resets whatever progress you’ve made toward a moratorium period clearing (like Pacific Cross’s 2 years) or AXA’s 3-year continuous coverage rule. If you already have a condition that needs regular check-ups or medication, staying put is usually the better move.

Does Thai Social Security cover pre-existing conditions?

Yes, in the sense that it doesn’t apply the same kind of pre-existing condition exclusions private insurers do. You need to be legally employed with an employer who registers you, and you’ll need at least 3 months of contributions in the 15 months before you need care to qualify for non-occupational illness benefits. But the condition itself isn’t a barrier the way it is with private insurance underwriting.

Do I need a broker to buy health insurance in Thailand?

Not strictly, but it helps, especially with any kind of medical history. A broker can compare your actual declared conditions against several insurers’ underwriting in parallel, something this article can’t do since it only covers what’s written in each policy’s general terms. We are not a broker ourselves; we’ve reviewed one Thailand-based broker’s approach to pre-existing conditions here if you want a starting point.

Sources Cited

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