Frequently asked questions

Yes, absolutely. Many people come here just to organize their thoughts. You are not committing to anything by reaching out. We only introduce agencies if you explicitly agree to share your details.

Some agencies in Japan can communicate in English or have bilingual staff, though this is not universal. Through PI-Thenics you can consult in English, and we can help match you with an agency that fits your language needs. Contracts will still be in Japanese, so asking for a translated summary or bringing a bilingual friend to the first meeting is a reasonable request.

Key things to confirm: the total price and what is included, additional fee conditions (overtime, travel, equipment), the cancellation policy, the definition of "success" if you are on a success-fee plan, and how your data and report will be handled after the investigation. If anything is unclear, ask for written clarification before signing. You have every right to take the contract away to review it or have someone translate it.

If you face a crime, immediate danger, stalking, or threats, contact the police (110) first. A PI is useful once safety is secured and you need documented facts — for example to verify behavior, locate someone, or prepare evidence for a lawyer. PIs have no law-enforcement powers; they observe, record, and report.

Bring: your goal (what you want to know or prove), a rough timeline of when things started, any facts you already have, your area, and a budget range. A short written summary helps — especially because you may need to communicate across a language gap. You do not need to have everything figured out.

Yes. Agencies registered under Japan's Private Investigation Business Act (探偵業法) operate legally. PIs may conduct surveillance, follow a subject in public, take photographs in public spaces, and compile reports. They cannot hack devices, install GPS without consent, make illegal recordings, or enter private property. Using their reports to harass, threaten, or discriminate is also illegal.

A licensed PI can follow and observe a subject in public, photograph behavior in public, compile factual reports, and gather publicly available information. They cannot access someone's phone or accounts without permission, install tracking devices on another person's property, make secret recordings in private spaces, enter homes or private premises, or take actions that amount to stalking.

Police first — especially if you feel in immediate danger. Contact the police (110) or your local women's consultation center (女性相談センター). You can also file a protective order request. A PI may help document incidents after your immediate safety is secured, but they are not a substitute for law enforcement when you are in danger. Embassies and foreign resident support groups can also help you navigate the system in English.

Yes. Japan's legal protections — including privacy rights and consumer protection rules for detective agencies — apply equally to foreign residents. You have the right to receive a written contract, a clear quote, and a proper explanation before signing anything. Agencies must refuse requests that are illegal or discriminatory regardless of who is asking.

Costs vary widely based on the type of investigation, number of investigators, hours, area, and urgency. Infidelity surveillance packages typically start in the low six figures (JPY) and rise quickly for multi-day work in large cities. Always ask for a full itemized quote — the headline price often excludes transport, vehicle fees, and the written report.

Confirm: number of investigators, minimum hours, whether vehicle and transport fees are included, report preparation fees, overtime rate, the exact definition of "success" in success-fee plans, and the cancellation policy. Do not sign if any of these are left vague.

A success fee means you pay a retainer up front, then an additional amount if a defined result is achieved. The catch: "success" can mean almost anything — confirming someone was at a location, a photograph, or full written evidence. Make sure the definition is in writing before you commit. An unclear success condition is a common source of disputes.

For hourly and package contracts, you pay for the investigation time whether or not a result is found. For success-fee plans, the contract defines what happens if the condition is not met — sometimes you lose the retainer. Clarify this in writing before starting.

Ask specifically: "Is vehicle and transport included?", "Are there overtime charges and when do they kick in?", "Does the written report cost extra?", "What happens if the subject moves outside the planned area?". Getting these in writing protects you. Agencies that refuse to answer clearly or pressure you to sign quickly are a red flag.

No. PI-Thenics is an independent guide and referral service. We help you understand the process, organize your situation, and — if you agree — introduce you to a suitable agency that fits your needs. We do not conduct investigations.

Navigating private investigator services in Japan is difficult even for Japanese speakers. For foreigners, the language barrier, unfamiliar legal system, and Japanese-only contracts add extra obstacles. PI-Thenics in English is designed to let you understand your options and consult without needing to know Japanese.

PI-Thenics reviews your message first. We only share your details with a matched agency if you tick the consent box. Not every consultation results in a referral — some situations are outside what agencies can help with, or no good match exists for your area.

No. A referral is just an introduction. You are free to get a quote, ask questions, and walk away without signing anything. If an agency pressures you unduly, you do not have to continue.