I worked at several Thai companies — can I combine the periods for the pension?

日本語版: タイで複数社で働いた場合、年金はどうなる？

For expat workers whose Thailand chapter spans multiple jobs, this question matters a lot: does the SSO recognize all my Thai employment together, even with gaps between jobs?

The short answer: yes, all contribution months are combined into a single total, regardless of which employer they came from or how many gaps there were between jobs. But there’s an operational catch: if your former Thai employers issued you separate SSO numbers (which is common for expats), you need all of them on hand. Let’s go through the rules and the gotchas.

The combination rule

Thailand’s old-age benefit is calculated on total contribution months across all your Thai employers. Gaps between jobs (when you were unemployed, abroad, or working elsewhere) simply don’t count as contribution months — they don’t reduce the total, they just don’t add to it. Here are two examples:

• Job 1 (3 years) + Job 2 (4 years) = 7 years (84 months) of combined contributions
• Job 1 (5 years) + 3-year break (returned home) + Job 2 (3 years) = 8 years (96 months) of combined contributions

The 3-year break in the second example doesn’t subtract anything — it just doesn’t add. The 8 years of actual employment count fully.

This matters most around the 180-month (15-year) threshold, where the benefit changes from a lump sum to a lifetime monthly pension. Someone with 8 years at one Thai employer and 8 years at another — with any size of gap between — has 16 years total and qualifies for the lifetime pension, even though no single employer reached 15 years on its own. See What’s the minimum contribution period? for the threshold details.

The catch: separate SSO numbers per employer

Here’s the operational reality that surprises most expat workers: in principle, Thailand’s SSO assigns one Social Security number per person, and that same number is supposed to follow you across employers. In practice, however, expat workers very frequently end up with separate SSO numbers issued by each Thai employer.

The reason is procedural rather than legal. When a new Thai employer registers a new hire with the SSO, the system assigns a fresh number unless the hire (or HR) explicitly tells the SSO “this person already has an existing SSO number — please use that one instead.” Local employees usually know to provide their existing number; expat employees often don’t, because no one tells them at hiring time. The result: a new number per new employer, with separate contribution records.

Operationally, this means: if you worked at three Thai companies and never carried over your number, the SSO has three separate records for you, each tied to a different number. Filing the application requires combining all three.

In summary: Thailand’s system is “one number per person” in principle, but functions as “one number per employer” for most expat workers in practice. If you assumed your number followed you, it probably didn’t.

What you need to file a combined claim

To file a single combined claim across multiple Thai employers, you need the following set for each employer (not just the total — the pairing matters):

• Company name (in English, preferably also in Thai)
• Approximate dates of employment (year-month precision is fine)
• The 13-digit SSO number issued by that employer

The reason these need to be paired (rather than just providing a list of numbers and a list of employers separately) is that the SSO uses the pairing to retrieve the right contribution record for each employer. Without pairing, the records can’t be combined cleanly.

What if you only have some of the numbers?

This is the most common situation. People often remember their first or most-recent employer’s number but can’t locate the others. The fix is straightforward: the missing numbers can be looked up at the SSO using your old passport copy and the company’s name.

See I don’t remember my SSO number for the lookup procedure and pricing. Briefly: with your old passport’s photo page and the company name (English or Thai), each missing number can be retrieved separately. Once all the numbers are in hand, the combined claim is filed normally.

Don’t forget about company name changes and acquisitions

A related blind spot: if a former Thai employer has been acquired, dissolved, or rebranded since you worked there, the SSO records may now be tied to the new company name rather than the original one. Searching under the original name can return “no records found,” while searching under the post-acquisition name pulls up the record cleanly. I’ve seen acquired-company cases where the record sits cleanly under the new name as soon as the staff are asked to check both — see I don’t remember my SSO number for an example.

If you don’t know what happened to your old employer, a quick English-language web search (“what is OLD_COMPANY_NAME Thailand now called”) usually surfaces the current name.

Section 39 (voluntary continuation): also counts

A small note for completeness: if you continued paying into social security voluntarily after leaving your last Thai employer (under Section 39, “voluntary continuation”), those months also count toward your total. They’re added to the combined total just like regular employer-paid months.

Two caveats with Section 39: (1) if you’re still actively enrolled in Section 39 today, you need to exit Section 39 before filing the claim — voluntary continuation counts as “active” for purposes of the eligibility check. (2) Voluntary contributions are calculated on a lower base (4,800 THB/month) than regular employee contributions (15,000 THB/month cap). If your last 60 months of contributions include Section 39 months, those months pull down the average wage used for the 20% calculation in the lifetime pension formula. For lump sums, Section 39 months simply add a bit to the total — no downside.

A note for anyone planning future Thai work

If you have an upcoming job in Thailand and want to avoid the multi-number tangle from the start, the procedure is simple: when you join, tell HR you already have an SSO number from previous Thai work and provide the number. They can register you against the existing record rather than creating a new one. I did this myself across my own Thai jobs, which is why my own number is unified. For past jobs where no one told you this — no problem, just have all the separate numbers ready when you file.

Read next

• The complete guide to Thailand’s old-age benefit
• I don’t remember my SSO number — what can I do?
• What’s the minimum contribution period?
• How much will I actually receive?

How I can help you with the application

Combining multiple SSO numbers across employers is exactly the kind of paperwork that benefits most from having someone do it for you. I take care of the entire application, including retrieving missing numbers and pairing them with the right employers. I tell you exactly which documents to prepare, you mail them to me in Thailand by international registered mail (or EMS within Thailand), and I file the application at the SSO on your behalf. For overseas recipients I follow up with the Royal Thai Embassy step as needed.

Service fee

The fee depends on the bank account you want to receive the benefit into:

This is a flat fee. There is no success fee and no additional charges. If it turns out that you are not eligible, I refund the full amount.

Number lookup service: If you don’t remember some or all of your SSO numbers, I can look them up for USD 60 (THB 2,000 / JPY 10,000) using your old passport copy and former employer names. (The lookup fee is for research time and is non-refundable.)

About the author

I’m Takehiko Nishizawa, originally from Saitama, Japan. I have been working for a Japanese company in Thailand for 25 years. During that time I have helped more than 40 former expat workers claim their social security old-age benefit from the Thai SSO. Every applicant who knew their Social Security number has successfully received their benefit. There have been no failed cases.

Get in touch

For questions or to start your application, please contact me through this form. I usually reply within 24 hours. You can also find me on X at @nisizawa.

This article provides general information about Thailand’s social security old-age benefit and is based on the author’s hands-on experience helping former expat workers file their claims. It does not constitute legal, tax, or financial advice. Tax treatment of the benefit varies by your country of residence — please consult a local tax or legal advisor for your specific situation. Procedures and amounts at the Social Security Office may change without notice; the description here reflects practice as of 2026.