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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.

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    Environmental Impact Assessment (EIA) Guide

    Complete guide to Thailand's EIA process for development projects, from determining requirements to obtaining approval.

    25 minUpdated: 2026Timeline: 6-18 monthsTHB 2-10 million (depending on project complexity)

    Overview

    This comprehensive guide walks you through every step of Environmental Impact Assessment (EIA) Guide, including required documents, timelines, and expert tips to help you navigate the process successfully.

    8 steps to complete

    Step-by-Step Process

    1

    Determine EIA Requirement

    1-2 weeks

    Check if project falls under 35+ categories requiring EIA approval from ONEP.

    Tips

    • Review latest ministerial notification
    • Some projects need EHIA (enhanced)
    2

    Engage Licensed Consultant

    2-4 weeks

    Hire ONEP-licensed EIA consultant to conduct studies and prepare report.

    Tips

    • Verify consultant license status
    • Check past approval rates
    3

    Conduct Baseline Studies

    2-4 months

    Study existing environmental conditions including air, water, noise, and ecology.

    Tips

    • Seasonal variations may require longer studies
    • Include socioeconomic assessments
    4

    Impact Assessment

    1-2 months

    Analyze potential environmental impacts and develop mitigation measures.

    Tips

    • Be comprehensive and realistic
    • Include construction and operation phases
    5

    Public Participation

    1-2 months

    Conduct public consultations and incorporate community feedback.

    Tips

    • Document all consultations
    • Address community concerns in report
    6

    Submit Report

    1 day

    Submit complete EIA report to ONEP for expert committee review.

    Documents Required

    • EIA report
    • Supporting studies
    • Public consultation records

    Tips

    • Ensure all sections complete
    • Pay submission fees
    7

    Committee Review

    3-6 months

    Expert committee reviews report, may request revisions or additional information.

    Tips

    • Respond promptly to queries
    • Attend committee presentations
    8

    Approval

    1-2 weeks

    Receive EIA approval allowing project to proceed.

    Tips

    • Approval valid for 5 years
    • Conditions must be followed

    Requirements

    • Project in EIA-required categories
    • Licensed EIA consultant
    • Baseline environmental studies
    • Public participation records
    • Mitigation plan

    Tips & Warnings

    Pro Tips

    • Start EIA process early in project planning
    • Budget for potential delays
    • Maintain good community relations
    • Prepare for post-approval monitoring requirements

    Important Warnings

    • Starting construction before EIA approval is criminal offense
    • False information leads to approval revocation
    • Non-compliance can shut down completed projects

    Video Guide Coming Soon

    We're working on a video walkthrough for this guide. Check back soon!

    Need Professional Help?

    Get expert assistance with this process from qualified legal professionals.

    Speak to a Lawyer

    Professional Legal Assistance

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

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