Koh Samui Building Regulations

Koh Samui offers some exceptional investment opportunities, but we also believe it’s important to issue a note of caution. While Thailand has a clear regulatory framework, enforcement can vary. Although regulatory checks and adherence to the rules have improved in recent years, it is not unheard of for projects, particularly in less mature markets like Koh Samui, to be developed in breach of regulations or build permits.

Even though many investors will rely entirely on the advice of a lawyer, we recommend that buyers take the time to understand the basic regulations for themselves. This puts you in a stronger position to clarify specific issues with your legal advisor, and ultimately leads to more informed decisions and better protection for your investment.

Building Regulations by Distance from the Beach

Before beginning any construction project, a building permit must be obtained from the local municipality office. Koh Samui’s coastal zoning regulations divide land into four areas based on distance from the beach:

• Area 1 – Up to 10 metres from the beach: No construction is permitted.
• Area 2 – Up to 50 metres from the beach: Only single-storey structures are allowed, with a maximum height of 6 metres, including the roof. Each building must not exceed 75 square metres in total area.
• Area 3 – Up to 200 metres from the beach: Buildings may be up to 12 metres high, with a maximum footprint of 2,000 square metres.
• Area 4 – More than 200 metres from the beach: The maximum building height is 12 metres, with no specific restriction on building size beyond compliance with other planning rules.

Note: All new buildings must be constructed with pitched or sloped roofs. Flat roofs are no longer permitted under current design regulations.

Building Regulations by Elevation Above Sea Level

Environmental restrictions on Koh Samui also vary depending on the elevation of the land:

• Level 1 – Land below 80 metres above sea level: In general, no additional restrictions apply. However, hotel developments must leave at least 50 percent of the land unbuilt and green. Residential projects with 10 or more units must include water and waste treatment systems. Infrastructure projects such as dams, golf courses, and airports are also subject to special rules.
• Level 2 – Land between 80 and 140 metres above sea level:
  • Only a single-family home may be constructed.
  • The land must be at least 100 square wah, or 400 square metres.
  • Maximum height is 6 metres.
  • At least 50 percent of the land must be left unbuilt and green.
  • The design must follow traditional Thai, tropical, or local architectural styles.
  • Roofs must cover 80 percent of the structure and use colours that blend with the natural environment.
  • An approved water drainage system is required.
• Level 3 – Land above 140 metres above sea level:
  • The same rules as Level 2 apply.
  • In addition, the maximum allowable building footprint is limited to 90 square metres.

Building Regulations by Land Gradient

Construction is also restricted based on the steepness of the land:

• Slopes between 35 and 50 degrees:
  • Only a single-family home is permitted.
  • Maximum building area is 80 square metres.
  • At least 75 percent of the land must be left unbuilt. Of this, at least 50 percent must be planted with native trees or vegetation.
  • The land parcel must be at least 120 square wah, or 480 square metres. If the plot is smaller, construction is not permitted.
• Slopes greater than 50 degrees: Construction is strictly prohibited.

Additional Rules for Hotel Operators and Developers

For larger developments such as hotels and residential projects, additional environmental regulations apply:

• Projects with 10 or more rooms must include:
  • Grease traps
  • Wastewater treatment systems
  • Proper stormwater drainage systems
• Projects must also:
  • Maintain access to the beach and avoid shoreline encroachment
  • Retain between 50 and 75 percent of the total land as green or open space
• An Environmental Impact Assessment (EIA), or Initial Environmental Examination (IEE), is generally required for:
  • Developments with more than 50 guest rooms
  • Land areas of 2,500 square metres or more
  • Subdivision of land into multiple plots
  • Construction of piers or other large-scale infrastructure