Affidavit of Foreign Law

Affidavit of Foreign Law. When a Thai court or administrative body must apply the law of another country, an affidavit of foreign law is the standard way to prove what that law is and how it applies. It is evidence about law, not about facts. A well-prepared affidavit saves time, reduces cross-examination and strengthens persuasion; a poorly-prepared one wastes cost and invites adjournment. This guide gives you a practitioner’s playbook: who prepares it, required contents and structure, authentication and translation, tactical uses, likely judicial treatment in Thailand, timing and costs, common pitfalls and ready-to-use drafting and instruction checklists.

Purpose and practical effect

Thai judges are not presumed to know the law of every foreign jurisdiction. An affidavit of foreign law explains:

• the substantive rule (statute, regulation, binding precedent) in the foreign system;

• how that rule has been interpreted by courts or authorities; and

• the reasoned application of those rules to the assumed facts of the Thai litigation.

If opposing counsel disputes the foreign law, the court will weigh competing expert affidavits and may call for more evidence or hearing time. The affidavit is evidence — the judge ultimately decides what the foreign law is worth.

Who should prepare it (and why credentials matter)

Prefer an affiant with recognizable and verifiable credentials:

• a practicing lawyer admitted in the foreign jurisdiction (best for recent case law and procedural practice); or

• an academic or specialist with demonstrable publications or case experience (good for doctrinal exposition).

The affiant should state admission year, practicing address, areas of expertise, notable cases or publications, and whether they can be produced for cross-examination or oral evidence (important if the court wants to question them).

Core structure — what judges want to see

Use a transparent, numbered structure so a judge or clerk can find key points quickly:

1. Heading: case title, court, party who instructs the expert;

2. Qualifications: short CV and statement of competence;

3. Instructions & scope: who instructed the affidavit, precise legal questions posed, documents provided and the facts to be assumed (annexed as “Agreed Facts”);

4. Statement of foreign law: short, numbered legal propositions with pinpoint citations to statutes/cases; avoid long narrative — courts like citable propositions;

5. Application to facts: reasoned application of each proposition to the assumed facts; keep law and application separate and labelled;

6. Sources & method: list primary authorities consulted (databases, official reporters) and the date of last search;

7. Caveats & conflicting authorities: identify divergent lines of authority and limits of opinion — candour increases credibility;

8. Exhibits: full copies of cited authorities (statute extracts, reported and unreported cases) with certified translations where necessary; and

9. Sworn attestation: signature, oath/notary block and place/date of swearing.

Number paragraphs and exhibits, and cross-refer throughout — judges and clerks will thank you.

Authentication and legalization — making it admissible in Thailand

For Thai courts/authorities you normally must do all of the following:

1. Swear/affirm the affidavit before a competent officer in the foreign jurisdiction (notary public or court official).

2. Apostille the notary signature if the foreign country is a Hague Convention member; otherwise obtain consular/legalization via the foreign ministry and the Thai consulate. This proves the authenticity of the notarization.

3. Certified Thai translation of the affidavit and all primary authorities cited. The translator should sign a translator’s declaration; some registries want the translator’s signature legalized too.

4. File originals or certified copies as required by the tribunal and retain apostilled originals for inspection.

Missing or incorrect legalization is the single most common cause of adjournments.

Exhibits & translations — how to present authorities

• Attach full text of statutes and cases relied upon (not just citations). For unreported decisions quote the controlling passages and include the entire judgment as an exhibit.

• Provide certified translations of each non-Thai authority into Thai (or an English translation if the court accepts English) and cross-reference exhibit numbers in the affidavit.

• Where a foreign law source is regionally variable (e.g., state/provincial divergence), specify the territorial scope of the opinion.

Keep exhibits paginated and produce a short index mapping each numbered legal proposition to the exhibit(s) that support it.

Practical drafting tips that win

• Use short, numbered legal propositions (e.g., “Proposition 3: Under X jurisdiction, a foreign divorce recognized if…”).

• Be explicit about assumed facts; never ask the expert to prove contested facts.

• Where multiple authorities conflict, identify the weight and dates of precedent and explain why you prefer one line.

• Ask the expert to include relevant procedural practice (how often courts apply the rule, whether oral testimony is common, typical remedies). Judges find this pragmatic guidance useful.

Tactical and procedural uses in Thailand

• Initial evidence: proves foreign law at filing stage; avoid last-minute affidavits.

• Rebuttal & reply: plan for an opposing expert and consider whether a joint expert conference or neutral court-appointed expert would save hearing time.

• Cross-examination: expect courts to permit oral questioning or video testimony — instruct the expert to be available.

• Administrative agencies: many agencies accept affidavits, but confirm whether originals or certified copies are required.

If the foreign law issue is decisive and contested, be prepared to fund a rebuttal affidavit or expert video appearance.

Timing & realistic costs

• Research & draft: 1–4 weeks for common jurisdictions; longer for obscure systems or complex comparative issues.

• Legalization & translation: allow 1–3 weeks extra (apostille/consulate timelines vary).

• Costs: from a few hundred USD for a simple opinion to several thousand for senior experts plus translation and legalization fees; urgent rush fees may apply.

Plan budgets and calendar early — the affidavit process rarely compresses well.

Common pitfalls and how to avoid them

• Unsigned or informal “opinion letters” instead of sworn, apostilled affidavits — treat unsigned letters as weak.

• Poor or inaccurate translations — always use legal translators with expertise in the source jurisdiction.

• Experts who cannot be reached for cross-examination — ensure the expert confirms availability and willingness to attend hearings (video link acceptable).

• Blurring facts and law — ensure the affidavit assumes (not proves) facts.

A pre-execution checklist (below) reduces these mistakes.

Model short affidavit clause (ready to adapt)

“I, [name], admitted as an advocate and solicitor in [jurisdiction] in [year], of [firm], being duly sworn, say: I have been instructed by [party] to advise on the law of [jurisdiction] on the following questions: (1) [precise question 1]; (2) [precise question 2]. The facts set out in Annex A are assumed. My opinion is based on the documents listed in Annex B. I have attached as exhibits the primary authorities relied upon. To the best of my knowledge and after the inquiries I describe, the matters contained in this affidavit are true.”

Attach: Annex A (assumed facts), Annex B (documents consulted), Exhibits 1–N (authorities).

Ready instruction checklist to send a foreign expert

1. Clear, numbered legal questions.

2. An agreed factual bundle (Annex A) to be assumed.

3. List of documents to provide as exhibits.

4. Deadline and any hearing dates.

5. Authentication instructions (swear before a notary + apostille/legalization).

6. Thai translation requirement and translator contact if preferred.

7. Confirmation of availability for oral testimony/video cross-examination.

8. Fee, payment terms and indemnity for reasonable costs.

Final practical note

Treat an affidavit of foreign law like an expert report: pick a credible author, be precise about questions and assumed facts, attach full primary authorities, authenticate and translate everything, and plan for rebuttal and oral testimony.