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    The content on this page is for general educational purposes and does not constitute legal advice. Every legal situation is unique. For matters involving investigation, arrest, litigation, or formal proceedings, consult a qualified legal professional.

    Environmental
    serious offence

    Marine Pollution / Illegal Discharge in Thailand

    Discharge of oil, harmful substances, sewage, or garbage from vessels into Thai waters in violation of MARPOL regulations.

    Last updated: February 2026
    Legal Sections

    Navigation in Thai Waters Act, Enhancement and Conservation of National Environmental Quality Act

    Maximum Penalty

    Imprisonment up to 5 years and/or fine up to THB 500,000; vessel detention possible

    Severity Level

    serious

    Definition

    Discharge of oil, harmful substances, sewage, or garbage from vessels into Thai waters in violation of MARPOL regulations. Under Thai law, this offence is classified as a serious offence within the category of Environmental.

    Elements of the Offence

    For a conviction, the prosecution must prove all of the following elements beyond reasonable doubt:

    1

    Discharge of polluting substance

    2

    Into Thai territorial waters or EEZ

    3

    Without proper treatment or authorization

    4

    Violation of MARPOL standards

    Penalties

    Maximum Penalty

    Imprisonment up to 5 years and/or fine up to THB 500,000; vessel detention possible

    Actual sentences depend on factors including the severity of the conduct, harm caused, prior convictions, and mitigating circumstances. Courts have discretion to impose lesser sentences within the statutory range.

    Possible Defences

    The following defences may be available depending on the circumstances:

    Discharge necessary for vessel safety

    Emergency to save life at sea

    Accidental discharge with proper reporting

    Compliance with MARPOL exceptions

    Note: The availability of defences depends on specific facts. Professional legal advice is essential.

    For Foreigners

    Special Considerations for Foreign Nationals

    Foreign vessels equally subject to Thai jurisdiction in territorial waters. Vessel may be detained pending fine payment. Master personally liable.

    When Legal Representation Matters

    If you are accused of marine pollution / illegal discharge or facing investigation, immediate legal representation is essential to protect your rights and build an effective defence.

    Anglo Siam Legal provides experienced legal services across Thailand for both Thai nationals and foreigners.

    Speak to a LawyerLegal Consultation

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