Thailand grades land by the document that comes with it, and the grade is stamped at the top of the deed as a coloured garuda, the state emblem. Anyone who has bought land on this island reads that colour before a single word of the text. It is the quickest signal of whether the boundaries were properly surveyed, whether the land can legally be sold at all, and whether a bank would lend against it.
One colour is a certainty: a red garuda means a Chanote, the only full ownership title Thailand issues, and every source agrees on that without exception. Below it the colours get slippery. Green and black are both used across the lesser Nor Sor 3 family, and even Thai law firms describe the shades inconsistently, so read the colour first but let your lawyer confirm the actual document type printed in Thai at the top. With that said, only three documents are worth serious money on Koh Lanta, one stands well above the other two, and everything beneath them is a reason to keep your deposit in your pocket.
The deeds you will actually meet
Chanote (Nor Sor 4 Jor)
Red garuda. A full, GPS-surveyed title with legally certain boundaries marked by concrete posts. Can be sold, mortgaged, leased and registered against without argument. This is the deed you want, and the only one we would buy without a very good reason.
Nor Sor 3 Gor
Green garuda, usually. A confirmed right of possession, surveyed against an aerial map but without the precise concrete corner posts of a Chanote. It sells without the 30-day public notice a plain Nor Sor 3 needs, can be mortgaged, and can be upgraded to a Chanote. Common here, and usually fine. The boundaries are the thing to check.
Nor Sor 3
Black garuda. A right of possession with no accurate survey behind it. A sale must be publicly advertised for 30 days before it can complete, and neighbouring boundaries are a genuine source of dispute. Buy this only with a lawyer who has walked the land.
Anything else
Sor Kor 1, Por Bor Tor 5, Sor Por Kor and the forestry-adjacent rest. Most of these are not even issued by the Land Department. At best they record that somebody once occupied a piece of ground and paid tax on it; they carry no ownership right, cannot be registered, cannot be sold to you and cannot be leased to you. Walk away.
Anyone handed a deed on this island reads the colour of the garuda before they read the name. Red is the one you want, and there is no polite way to say the others are worth less.
What your lawyer reads on the back
The front of a deed is the part everyone photographs: the parcel map, the area in rai, the owner's name, the garuda. It is also the part that tells you almost nothing about whether the land is safe to buy. The document that matters is the back.
The reverse of a Thai title is a running register, the saraban, where the Land Office logs every event that has ever touched the land: each sale and inheritance, every mortgage, every registered lease, every usufruct, superficies and right of way, and any court seizure or injunction. Each entry is dated, signed and stamped. A plot can look completely clean from the front and carry a bank's mortgage, a fifteen-year lease and a neighbour's right to drive across it on the back.
Those registered rights are the ones that outlive the sale. A mortgage has to be formally discharged before the land can transfer cleanly; a registered lease binds you as the new owner; a right of way stays with the land whoever buys it. That is exactly why the copy a seller hands you proves nothing on its own. Your lawyer pulls a fresh certified copy straight from the Land Office and reads the reverse, line by line, against everything you have been told.
What due diligence actually checks
Usually a week or two, and a few tens of thousands of baht. It is the cheapest part of the transaction and the only part that can stop you making an expensive mistake.
The title itself
A certified copy pulled from the Land Office, not the seller's photocopy. Who owns it, what class of deed it is, how long they have held it, and whether the chain of ownership before them makes sense. It also confirms the seller is who they claim to be and, if they are married, that their spouse has consented to the sale in writing, which Thai law requires for jointly held land.
Encumbrances on the back
Mortgages, existing leases, usufructs, servitudes, court injunctions. All of it is registered on the reverse of the deed, and any of it can survive your purchase.
The boundaries, on the ground
The deed says where the land is. A surveyor says where it actually is. On a Nor Sor 3 these are two different questions, and on any hillside plot on this island they are worth asking.
Access to the road
A plot with no registered right of way is a plot you may not be able to legally reach. A neighbour's goodwill is not a legal access right, and goodwill is not inherited by the next neighbour.
The building permit
The house has to have been legally permitted to be legally sold as a building, and setbacks from the sea, the road and the boundary are enforced here more often than people expect.
Zoning and taxes
Koh Lanta runs on Krabi's coastal zoning, not a generic national rule, and the limits are stricter than people expect: no building at all within 20 metres of the high-water mark, then height and land-coverage caps that tighten the closer you sit to the sea. Outstanding land tax, and whether the seller has actually paid it, is worth settling before you inherit the answer.
The park and forest boundary
Mu Ko Lanta National Park runs across the south of Ko Lanta Yai, and a title can occasionally be issued over land that is legally state forest or park. A standard title search does not catch this on its own, so any parcel near the park, or a mangrove or forest reserve, needs its boundary checked against the gazetted line before you commit.
Every listing here states its deed class
It is on the listing page, next to the price, in the colour of its own garuda. No listing on this site hides it.
General orientation only, and not legal, tax or financial advice. Thai property law changes, and every transaction turns on its own facts. Always engage a qualified Thai property lawyer, who is not the seller's, before you commit to anything.