Burned some Opus 4.7 Adaptive tokens on this question. here's the result.
3. Where the "financial stability" idea actually comes from
The 400,000 THB / 40,000 THB figure is real — but it belongs to immigration law, not marriage law. Specifically, it is part of the requirements under the Immigration Act B.E. 2522 (1979) and Royal Thai Police Order No.
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(and successor orders) for a foreigner who wants a one-year extension of stay on the basis of marriage to a Thai national (commonly called the "marriage visa," technically a Non-Immigrant O extension).
The financial requirements for that extension are:
400,000 THB in a Thai bank account in the foreigner's sole name, on deposit for at least 2 months before the extension application (3 months for renewals at most offices), OR
Provable monthly income of 40,000 THB (embassy letter or 12 months of foreign-source bank deposits).
The marriage itself is registered first; the visa extension is a separate, later application made at Immigration, not at the Amphur.
Same-sex couples and the visa side
This is where the picture is less mature than the marriage law itself. Fragomen's April 2026 immigration update confirms the Thai government has implemented immigration pathways for same-sex foreign national spouses who are legally married to a Thai national or to a foreign visa holder eligible to sponsor a spouse and that a same-sex spouse may submit an application for a 90-day Non-Immigrant "O" visa at a Thai embassy overseas, with both Thai (Kor Ror 3) and foreign marriage certificates accepted. A same-sex spouse legally married to a Thai national may apply for a long-stay Thai spousal visa through the Thai Immigration Bureau, and if married abroad, a Family Status Registration (Kor Ror 22) must first be done in Thailand. Fragomen + 2
The financial criteria appear to be applied uniformly to same-sex couples (same 400k/40k rule), but same-sex spouse-of-foreigner dependent visas applied for in-country are still being finalized per Fragomen — implementation gaps remain. Be alert that some immigration offices outside Bangkok have been slow to update, and individual officers have discretion under s. 35 of the Immigration Act.
A real wrinkle: foreign wife of Thai husband
Historically, in practice (not in the black-letter rule), Thai Immigration applied the financial test more loosely to foreign wives of Thai husbands than to foreign husbands of Thai wives — sometimes accepting the Thai husband's tax-paying status instead. The legal text never actually said this; it was a pattern of administrative practice rooted in patriarchal assumptions. With the gender-neutral CCC, that practice has no remaining doctrinal basis, but it may persist administratively. For a same-sex couple this is double-edged: you cannot rely on the lenient "foreign wife" practice, but neither should you be discriminated against compared to opposite-sex couples.
4. Direct answers to your questions
Lesbian couple (foreign woman + Thai woman)
To marry: Affirmation of Freedom to Marry from foreigner's embassy (translated, MFA-legalized), passport, plus the Thai partner's ID and Tabien Baan. Two witnesses. No financial requirement.
To live in Thailand on the basis of that marriage: 400k THB / 40k THB rule applies, same as anyone else. The 310-day rule may apply to one of them if she was recently divorced from a man.
Gay male couple (foreign man + Thai man)
To marry: Identical document list — Affirmation, passport, ID, Tabien Baan, two witnesses. No financial requirement. The 310-day rule effectively doesn't apply.
To live in Thailand on the basis of that marriage: Same 400k/40k rule.
5. What I would push back on, as a fellow practitioner
Be skeptical of any source — including a registrar — asserting a financial requirement for the marriage itself. Ask them to cite the section of the CCC or the ministerial regulation. They cannot, because none exists.
Don't rely on legal-blog summaries from law firms with marketing incentives to oversell complexity. The cleanest authorities are: the CCC itself (Book V, ss. 1435–1535 as amended); DOPA's marriage registration regulations; the Immigration Act B.E. 2522 and current Police Order for visa rules; and Library of Congress / OHCHR / UNDP commentary for neutral overviews.
If your client was told by a specific Amphur that finances are required, get it in writing, then escalate. There have already been documented inconsistencies in early implementation — some district offices were under-trained on the new gender-neutral forms in the first months after 23 January 2025. Twelve months in, this should not still be happening, but it is.
If the question is actually about a visa, not a marriage, then yes, financial proof is required — but frame it accurately so the client doesn't think marriage itself is being conditioned on wealth.