400,000 Baht for a Thai Visa Extension: The Bank Rules That Catch Most Applicants Out

Most applicants preparing for a Thai Non-Immigrant O visa extension know about the 400,000 Baht bank requirement. Far fewer know that having the money in the account is only one part of what immigration will check. A name spelled differently across documents, a bank book updated on a different day from the bank letter, or a balance that dipped below the threshold even once during the required period are all grounds for refusal. This guide covers the complete picture: what the financial requirement actually is, how name consistency is enforced, what your bank documents must show on the day of your appointment, and the bank-level rules that go beyond what immigration itself requires.

The 400,000 Baht Requirement: What the Official Rule Says

The financial requirement for a one-year extension of stay based on the Non-Immigrant O visa for marriage is set by Thai immigration regulations and confirmed on the official Thai Immigration Bureau website at immigration.go.th. You must demonstrate one of the following:

• A deposit of at least 400,000 Baht maintained in a Thai bank account in Thailand for at least two months before the application date, or
• A verified monthly income of at least 40,000 Baht per month, demonstrated through documents such as an individual income tax return with payment receipt, evidence of receiving a retirement pension, evidence of receiving interest from a deposit account, or other evidence of funds issued by a relevant agency

Both options are confirmed directly on the official Thai Immigration Bureau website. The income method does not require an embassy income letter for the marriage-based Non-O extension. That requirement applies to the Non-Immigrant O-A retirement visa, which has a higher income threshold of 65,000 Baht per month. For the marriage-based Non-O extension, the accepted documents for proving income are tax records, pension documentation, interest statements or equivalent official evidence.

The account must be in the applicant's name only. A joint account does not satisfy the requirement. A fixed deposit account at a Thai bank counts toward the balance, but you must bring the fixed deposit certificate to your appointment alongside the passbook and bank letter.

The Balance Must Not Drop: Not Even for One Day

This is the point that catches the most applicants. The 400,000 Baht must not fall below that level at any point during the required seasoning period before your application. The bank statement submitted to immigration shows a full transaction history, not just the current balance on the day of the letter. An immigration officer reviewing the statement can see every deposit and withdrawal and will identify any day where the balance fell below the threshold.

A single day below 400,000 Baht, whether caused by a scheduled payment, a card transaction, a transfer you forgot about, or an ATM withdrawal, is sufficient grounds for an officer to refuse the extension. The only remedy at that point is to restore the balance to above 400,000 Baht and restart the seasoning period from that date. You cannot simply top up the account immediately before the appointment and present the current balance as evidence.

Thai Visa Services, which works extensively with Thai immigration offices, states this explicitly: "Do not withdraw below the thresholds during these periods. Immigration can and does check bank records, and failing to maintain the balance can result in extension denial at your next renewal."

In practical terms this means treating your Thai immigration account as a dedicated account during the seasoning period. Set up a separate account if necessary to avoid accidental withdrawals from the funds you are keeping for immigration purposes.

How Long Must the Funds Be in the Account?

The standard immigration requirement for a Non-Immigrant O extension based on marriage is two months of maintained balance before the application date. This is the minimum period set by Thai immigration regulations as confirmed by Thailand Law Online and multiple immigration practitioners.

However, individual banks apply their own requirements that go beyond the immigration minimum, and it is important to understand how these work in practice before you make any decisions about your account.

Based on our direct experience, some Thai banks operate a two-tier policy when issuing immigration letters. If the 400,000 Baht has been maintained in the account for four months or more, the bank will issue the immigration letter without any additional conditions. However, if the funds have been in the account for less than four months but at least the two months required by immigration, some banks will only issue the letter on the condition that you agree to lock the 400,000 Baht for four months from the date the letter is issued. This means that if you collect your bank letter in January and the money has only been there since November, the bank may lock those funds until April regardless of when your visa extension is approved. The lock runs from the letter date, not from the date the money was deposited, and you will not have access to those funds until the four-month period expires.

This policy varies between banks and between individual branches. We recommend confirming the current terms directly with your specific bank before your appointment. The safest approach is to have the full 400,000 Baht in place at least four months before your intended appointment date, which removes any possibility of a lock being applied and gives you the most straightforward path to obtaining the required letter.

The Bank Documents You Must Bring and Why They Must Match

For a Non-Immigrant O extension based on marriage at a Thai immigration office, the financial documents required are:

• An original bank letter on official bank letterhead, confirming the account balance and account holder details, issued by the bank
• An updated bank book showing the current balance and recent transaction history
• Photocopies of every page of the bank book that contains entries

In the experience of our team working with clients at Surin Immigration Office, immigration officers require that the bank letter and the updated bank book carry the same date, which is the date of the appointment itself. Both documents must show a matching balance on that date.

A bank letter issued the day before the appointment, or a bank book updated earlier in the week while the letter was obtained on the day, has been refused at the counter. The safest and most reliable approach is to visit your bank on the morning of your immigration appointment, have the bank book updated and the official letter issued on the same visit, and proceed directly to the immigration office. Do not allow any transactions on the account between obtaining the documents and presenting them.

This same-day requirement reflects a broader principle that Thai immigration applies to financial documentation: the documents must represent the account status at the moment of the application, not at some earlier point that may no longer be accurate.

Name Consistency Across All Documents

One of the most common and most avoidable reasons for a Thai visa extension refusal is a name discrepancy across documents. Thai immigration requires that the name on your passport, the name on your visa, and the name on your bank account documentation are identical. This sounds straightforward, but in practice it creates problems for a significant number of applicants.

The most common variations that cause problems are:

• A middle name appearing in full on the passport but as an initial only on the bank account
• A middle name present on the passport but absent entirely from the bank account
• A first name abbreviated or shortened on one document but given in full on another
• A hyphenated name treated as two separate names on one document and a single hyphenated name on another

The Royal Thai Embassy in Seoul states explicitly on the official Thai e-Visa portal: "All information should be identical to the passport. Application with wrong information is non-revisable and visa fees are non-refundable, and will be canceled and result in re-application." ThaiEmbassy.com, an established Thai visa information service, confirms: "Your name must appear exactly as shown in your passport's MRZ. A single typo can invalidate your application."

For immigration purposes, your name is what appears in the machine-readable zone at the bottom of your passport biographical page. That is the authoritative version. Every other document, your bank account, your TM30 address registration, your marriage certificate translation, must match that version exactly.

If there is a discrepancy between your passport name and your bank account name, the time to resolve it is not on the morning of your immigration appointment. Contact your bank well in advance and request that your account name be updated to match your passport name precisely, including all middle names as they appear in the MRZ. Bring documentation to the bank confirming the correct name if required.

Other Documents Required for a Non-O Marriage Extension

The financial and bank documents are only one part of the full document set. For a one-year extension of stay based on marriage, Thai immigration also requires the following. Note that requirements can vary between individual immigration offices, and Surin Immigration Office may request documents in addition to or instead of those listed here. Always confirm current local requirements before your appointment.

• Completed TM7 extension application form
• Valid passport with at least one blank page
• Current Non-Immigrant O visa and all previous extension stamps
• Original marriage certificate and a certified translation if not in Thai
• Thai spouse's original national ID card and house registration document (Tabien Baan)
• Four photographs of the couple together taken at your home, showing the interior of the residence
• A map showing the location of your residence
• TM30 residence notification receipt confirming your address has been reported to immigration
• Photocopies of all documents including every stamped page of the passport
• Extension fee of 1,900 Baht

Every document in the set must show your name exactly as it appears in your passport. This applies to the TM30, the marriage certificate, the translation and any other form that carries your name. An officer who notices a discrepancy on any document in the package has grounds to ask for clarification or to refuse the application.

What to Do Before Your Appointment

Based on our experience assisting clients at Surin Immigration Office, the following preparation reduces the risk of a problem on the day of the appointment to close to zero:

• Check your bank balance every day during the seasoning period. Set a calendar reminder and make it a routine. One overlooked automatic payment can end the seasoning period and force you to start again.
• Confirm with your bank how many months of maintained balance they require before they will issue an immigration letter, and whether any lock conditions apply. Do not assume two months is sufficient for your bank.
• On the morning of your appointment, go to your bank first. Have the bank book updated and the official letter issued on the same visit. Check that both documents show the same date and the same balance before leaving the bank.
• Check the name on your bank account against the machine-readable zone in your passport. If there is any difference at all, contact your bank to correct it before the appointment, not after.
• Bring both original documents and photocopies of everything. Immigration offices in Thailand typically require a photocopy of every document presented. Arriving without copies is a common cause of delay.
• Arrive early. Surin Immigration Office, like most provincial offices, operates on a first-come basis and appointment slots fill early in the day.

If you are unsure about any aspect of your documentation before your appointment, contact our team. We assist clients with Non-O extensions at Surin Immigration Office and can review your documents in advance to identify any issues before they become a problem at the counter.