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Thailand Private Investigators

Since 1994 – Competitive and Realistic rates in Thailand, Bangkok, Pattaya – All of Country

Rated as one of the best private investigations companies in the world.

WITH HEADQUARTERS IN LONDON & REGIONAL OFFICES. all our local Private Investigators in Thailand and subcontractors are compliant with Thailand’s private investigation regulations, holding the necessary permits in accordance with the provisions set out by Thailand law.

Full services Agency for private clients, business, lawyers, families and VIPs.


LOI Investigations established investigators since 1994 with an independently audited 98.9% success rate (March 2024).

LOI Investigations offers a comprehensive range of services tailored for the Thailand market. We cater for undercover sex vacations real time surveillance, pre-martial background in-depth checks, post vacation investigations.

Private individuals, businesses, corporate investigations & intelligence, Crypto Currency and Bitcoin pre-due diligence, missing-stolen funds tracing and recovery. Offering services that range from Background Checks & KYC to Technical Counter Surveillance Measures. Our Surveillance solutions are led by former military intelligence officers, ensuring the highest level of professionalism. With a focus on Family Law, we provide tailored solutions that meet the unique legal landscape of Thailand including Relationship Matters, Family Law issues, Supply Chain – Risk & Fraud. We also offer Global Database Access and Asset Tracing & Fraud services for comprehensive investigative needs. Additionally, we provide full services for all types of investigations involved. Our team includes local Private investigators Thailand covering the whole of Thailand and South East Asia, as well as private detectives and private investigators.

Difficult and unusual cases, hidden and hard to obtain information. 
Totally confidential.

Call now for a free consultation

International Free Toll: + 44 800 1 934 999

Calls answered 24hrs a day by qualified local private investigators based in Thailand

Why Choose LOI Local private investigators in Thailand?

  • Originally established and trading since 1994.
  • Experienced Team: Recognised worldwide leading investigation and intelligence professionals, also including former military intelligence officers and senior surveillance experts.
  • Tailored Solutions & Advance Technology: Each service is customized to meet the unique challenges and objectives of our private, business, and multinational clients.

Premarital Background Checks

LOI Investigations excels in conducting meticulous and precise premarital background checks, ensuring that you have a comprehensive understanding of your prospective partner’s history. Our private investigation services extend to verifying personal backgrounds, financial stability, and any criminal records, providing you with the clarity and assurance needed for such a significant life decision. Our seasoned private investigators Thailand handle each case with the utmost discretion, guaranteeing confidentiality and expediency. Place your trust in LOI Investigations for thorough and reliable premarital investigations.

Stolen Jewellery, Art, and High-Value Items Investigation Room

Jewellery Theft

At LOI Research, we specialize in the recovery of stolen jewellery, art, and high-value items. Our dedicated team of private investigators in Thailand is renowned for their expertise in tracking and recovering valuable items that have been lost or stolen. Our services are not just limited to the UK; we operate globally, providing our clients with the best chance of recovering their valuables.

missing persons investigation

Missing Persons Tracing

Searching for a missing person in Thailand or worldwide? LOI Investigations offers private investigator services to locate lost friends, family members, or debtors. Utilizing the latest investigative techniques, our experienced team provides effective and discreet missing persons investigations.

Worldwide Phone Tracing Service

LOI Investigations offers a law-compliant Worldwide Mobile Phone and Landline Tracing service. Obtain the full name, registered address, duration at the address, and additional connected information with utmost confidentiality.


At Line of Inquiry, we offer in-house surveillance investigators led by experienced professionals, including a former military intelligence officer and a Senior Surveillance officer with 23 years’ experience. Our surveillance services, available across Thailand and worldwide, include mobile and static solutions, under-cover work, and the use of advanced technology such as trackers, electronic bugs, and military-grade drones. Whether discreet or covert, our fool-proof method ensures professional evidence gathering to meet your needs.

missing persons investigation

Relationship Matters, Family Issues and Divorce

Dealing with family issues and divorce? Line of Inquiry offers specialized private investigator services in Thailand to assist in personal and financial matters, including hidden assets, pre-divorce background checks, and post-separation surveillance. Whether you suspect infidelity, need to assess financial status, or are concerned about child well-being, our experienced investigators handle these delicate situations with discretion and sensitivity. Contact Line of Inquiry to navigate family disputes and divorce with confidence and peace of mind.


Private Clients

We at Line of Inquiry offer a range of services for private clients, including missing persons tracing, background checks, surveillance, and asset tracing. Specialized services are also available for relationship matters, identity theft, and blackmail. Our experienced team utilizes advanced investigative techniques to provide effective and discreet solutions tailored to individual needs.


Line of Inquiry offers a comprehensive suite of services tailored for businesses. These include business intelligence, asset tracing, debtor tracing, and competitive intelligence. Specialized services extend to acquisition and mergers, investment intelligence, and supply chain risk mitigation. Our experienced team employs advanced technological tools and investigative techniques to ensure your business stays ahead in a competitive market.

Relationship Matters & Family Issues

Comprehensive support in family law matters, including relationship disputes and divorce cases. Our services extend to missing persons tracing, surveillance, and personal protection against blackmail. Utilizing advanced technology and an experienced team, we offer discreet and effective solutions tailored to the unique challenges faced by families.

Cyber Investigations

We offer a comprehensive range of Cyber Investigation services, including tackling catfishing, social media harassment, and cyber threats. Our expertise extends to cryptocurrency investigations and technical counter-surveillance. Utilizing a team of former FBI agents, and hacking specialists, we provide robust solutions to protect both individuals and businesses from various cyber risks.


We at Line of Inquiry specialize in litigation investigation and support services, offering worldwide assistance for both civil and criminal cases. Our services include fraud investigations, asset tracing, and family law support. Utilizing advanced technology and techniques, we work closely with legal teams to provide expert analysis and testimony, adhering to the highest ethical standards.

Contact Us

For expert private investigation and intelligence consultancy services in acquiring hard-to-obtain confidential information globally, look no further.