Form AK, Form J, and Form T: Which FTA Countries Do They Cover?

Thailand is party to a growing list of free trade agreements, and each one comes with its own certificate of origin, identified by a letter code that traders and forwarders tend to reference casually — Form AK, Form J, Form T, and others. To someone new to trade documentation, the alphabet soup can be genuinely confusing: the forms look structurally similar, they serve the same basic purpose, and the letters themselves don't obviously map to anything without context.

The key to making sense of it is remembering that each letter code ties directly to one specific agreement, and each agreement covers one specific country pairing (or group of countries, in the case of a regional bloc agreement). Once that link is clear, matching the right form to a given shipment becomes a matter of correctly identifying which agreement covers the trade lane in question — not memorizing an arbitrary list of codes.

What a Certificate of Origin Actually Does

Before comparing the specific forms, it's worth being clear about what a certificate of origin accomplishes generally. Under a free trade agreement, goods that qualify as "originating" in one member country — according to that agreement's specific rules of origin — are eligible for reduced or eliminated import duty when entering another member country covered by the same agreement, instead of paying the standard most-favored-nation duty rate that would otherwise apply.

A certificate of origin is the document that formally supports that claim: it's issued by a recognized authority in the exporting country, states the goods' description and HS code classification, and declares that the goods meet the origin criteria of the specific agreement being invoked. Without a valid certificate matching the correct agreement, an importer generally can't claim the preferential rate, even if the goods would have qualified had the paperwork been in order.

A certificate of origin isn't necessarily accepted at face value forever, either. Destination customs authorities can, and periodically do, request verification of an origin claim after the goods have already cleared — checking the issuing authority's records, or asking the exporter to substantiate how the goods met the applicable rules of origin. If that verification can't be satisfied, the preferential treatment already granted can be revoked retroactively, and the importer becomes liable for the duty difference. This is one reason exporters are generally expected to retain the records supporting an origin claim, not just the certificate itself, for a period after the shipment moves.

Form AK: ASEAN–Korea Free Trade Agreement

Form AK is the certificate of origin used to claim preferential treatment under the ASEAN–Korea Free Trade Agreement, a regional agreement between the ASEAN member states as a bloc and South Korea. For a Thai exporter shipping to South Korea, or a Thai importer bringing goods in from South Korea, Form AK is the relevant certificate — provided the goods meet the specific rules of origin set out under that agreement.

Because it's a bloc-to-country agreement rather than a purely bilateral one, Form AK also covers trade between South Korea and other ASEAN member states, using the same rules of origin framework across all of them. The letter code "AK" itself is a mnemonic shorthand — ASEAN and Korea — that's become the standard way the industry refers to this specific certificate, distinguishing it clearly from certificates tied to Thailand's other FTAs.

Form J: Japan–Thailand Economic Partnership Agreement

Form J is the certificate of origin used specifically under the Japan–Thailand Economic Partnership Agreement, commonly abbreviated JTEPA — a bilateral agreement between Thailand and Japan alone, distinct from the broader ASEAN–Japan Comprehensive Economic Partnership that also exists. This distinction matters: Thailand actually has two separate agreements that touch on trade with Japan, one bilateral and one through the ASEAN bloc, and each has its own certificate of origin with its own rules.

Form J applies specifically to goods traded directly between Thailand and Japan under the bilateral JTEPA framework. An exporter or importer needs to confirm which of the two Japan-related agreements is actually the more favorable or applicable one for a given shipment, since the rules of origin, product coverage, and duty schedules can differ between JTEPA and the ASEAN-wide agreement — using Form J assumes the shipment is specifically invoking the bilateral agreement rather than the regional one.

Form T: Thailand-Specific Agreement Designation

Form T is used for a Thailand-specific bilateral or regional agreement designated with that letter, and it's worth being deliberate about not confusing it with Form D, the well-known certificate used for trade within ASEAN under the ASEAN Trade in Goods Agreement (ATIGA). The two are structurally similar — both are certificates of origin supporting duty preference — but they're tied to entirely different agreements with different member coverage and different rules of origin.

Because the specific agreement Form T is tied to is narrower and more particular to Thailand's own bilateral trade relationships, exporters and importers should confirm directly with Thailand's Department of Foreign Trade, or with a customs broker familiar with the current list of Thailand's active FTAs, exactly which agreement a given Form T certificate is being issued under for their specific trade lane, since Thailand's roster of bilateral and regional agreements has continued to expand over time.

Why Getting the Right Form Matters

Using the correct certificate of origin form isn't a formality that can be approximated — destination customs authorities check that the form presented matches the agreement being invoked, and that the goods described actually meet that specific agreement's rules of origin. Rules of origin differ meaningfully between agreements: a product that qualifies as originating under one FTA's criteria might not qualify under another's, even for trade with the same country, if two different agreements happen to both cover that trade lane.

Getting the wrong form, or a form whose underlying agreement the goods don't actually qualify under, typically results in the preferential duty claim being denied, meaning the importer pays the standard duty rate instead — an outcome that can significantly change the landed cost of a shipment if the preferential margin was built into the purchase decision. Confirming the correct form and verifying origin eligibility before shipping, rather than after arrival, avoids that kind of costly surprise at destination customs.

Why Thailand Has So Many Certificate-of-Origin Forms

The underlying reason a Thai exporter or importer can end up dealing with several differently lettered certificates is that Thailand is simultaneously a party to multiple, independently negotiated free trade agreements — some at the ASEAN bloc level, some bilateral, and some regional beyond ASEAN. Each agreement was negotiated separately, on its own timeline, often with its own rules of origin philosophy, and each therefore ended up with its own certificate format and letter designation rather than all being folded into a single universal document.

This is a common feature of countries with an active trade-agreement portfolio, not something specific to Thailand's approach, but it does mean that the practical burden of keeping track of which form applies to which country pair falls on the businesses actually trading, or on the brokers and forwarders they rely on. Staying current matters because Thailand's list of active agreements has continued to grow over time, and a business that hasn't reviewed its trade lanes recently may be missing out on a preferential form it could legitimately use, or worse, still relying on an outdated understanding of which form applies to a given route.

In practice, this also means a single trade lane can sometimes be covered by more than one overlapping agreement, each with its own certificate and its own duty schedule — the Japan relationship discussed above is one example, but it's not the only case where a business exporting to a given country needs to check whether more than one agreement applies. Where more than one option exists, the choice generally comes down to comparing which agreement's rules of origin the goods can actually satisfy, and which one offers the more favorable duty outcome for that specific product. A customs broker or forwarder who regularly handles a given trade lane is often the fastest way to get a current, practical answer to that comparison, rather than working through each agreement's published rules independently for every shipment.