Speedboats from Laem Sok and Laem Ngop, and a thirty-minute hop from Koh Kood at 400–500 baht. 436 registered residents. The island health centre has no inpatient beds; the school stops at Prathom 6. Power arrived by 22 kV submarine cable in 2015 and the unit cost fell from 8.75 to 3.02 baht. There is no mains water. Whether the island is inside Mu Ko Chang National Park is unresolved — section 04.
Getting there, and what we will not print
Koh Mak sits between Koh Chang and Koh Kood, and is reached from two mainland piers in Trat or from Koh Kood. Everything in the table below is read off an operator’s own schedule or a Trat provincial government advisory.
| Route | Departures | Crossing | Fare, baht |
|---|---|---|---|
| Laem Sok - Koh Mak (province advisory, speedboat) | 11:30, 12:30, 15:00, 16:00 | not published | not published |
| Laem Ngop (Krom Luang Chumphon pier) - Koh Mak | 10:00, 16:00 | not published | not published |
| Koh Kood - Koh Mak (Boonsiri) | 11:00 | 30 min | 400 |
| Koh Kood - Koh Mak (Koh Kood Express) | 09:00, 11:30, 14:00, 14:30 | 30 min | 500 |
| Koh Mak (Ao Nid) - Koh Kood (Koh Kood Express) | 10:30, 12:15, 13:30, 16:30 | 30 min | 500 |
| Koh Mak - Bangkok Suvarnabhumi (Koh Kood Express, boat + minivan) | 09:00, arriving 17:00 | 8 hr | 1,100 |
Why two cells say “not published”. The province lists the mainland sailings without times of crossing or fares, and Boonsiri publishes its timetables as images rather than text. The one automated reading we got of the Laem Sok to Koh Mak row returned a thirty-minute crossing, which is the Koh Kood to Koh Mak duration and cannot be right for a mainland run. Rather than average two numbers we could not read, we have left the cells empty and said why. Phone the operator.
Out of season
Koh Mak is on the eastern seaboard, so its wet season follows the southwest monsoon, which the Thai Meteorological Department puts over Thailand from about mid-May to mid-October. That is the reverse of the Gulf islands off Surat Thani, where the heavy weather arrives with the northeast monsoon from October.
The evidence that low season changes access here is commercial rather than meteorological. Boonsiri publishes two separate seasonal timetables — a high-season sheet dated 1 January to 31 May 2026 and a low-season sheet dated 4 June to 30 September 2026 — which is a clear statement from the operator that service materially changes on about 1 June and again on about 1 October. What exactly changes on the Koh Mak legs we cannot tell you, because those sheets are images.
There is one telling official signal. In August 2023 DASTA ran a campaign whose stated purpose was to make travellers aware that Koh Mak can be visited all year round, explicitly to stimulate the island economy in low season. A state agency campaigning to persuade people the island is reachable is itself evidence of what the low season feels like from the mainland.
What the island actually has
| What | Where | Detail |
|---|---|---|
| Public health | Koh Mak Sub-district Health Promoting Hospital, 32 Moo 1 | 0 beds in actual use (MOPH registry) |
| School | Ban Koh Mak School (Sathit Sutthiwong), 32/1 | Kindergarten 2-3 and Prathom 1-6; 83 pupils; no secondary |
| Local authority | Koh Mak Subdistrict Administrative Organisation, 34/2 Moo 1 | 039-510748 |
| Referral hospital | Phra Piya Maharat Hospital, Mueang Trat (formerly Trat Hospital) | 395 beds, service level S |
| Registered residents | Tambon Koh Mak | 436 (219 male, 217 female), April 2024 |
The two numbers to hold together are zero inpatient beds and 83 pupils, none above Prathom 6. A sub-district health promoting hospital is the bottom tier of the Thai public system: primary care, no admissions, no surgery. Anything requiring a bed means a boat, and the realistic first stop is Koh Kood Hospital thirty minutes away, which is itself a level-F3 community hospital with seven beds in use. The provincial hospital in Mueang Trat — Phra Piya Maharat, renamed by royal grant in March 2026, 395 beds — is the tertiary referral point.
For a family, the school is the constraint that decides it. Ban Koh Mak School teaches kindergarten through Prathom 6 and stops there. After Prathom 6, a child leaves the island for secondary school. That is not a criticism of the school; it is arithmetic that follows from 436 registered residents.
The park boundary, and why we are leaving it open
Of everything on this page, this is the item most likely to cost someone money, so it gets the longest answer and the least confident one.
The founding instrument is the royal decree of 31 December 1982 declaring the land of Koh Chang and neighbouring islands, in Tambon Koh Chang and Tambon Koh Mak, Laem Ngop district, a national park. We were able to reach the decree text in the Department of National Parks’ own file drawer. Its section 3 does the operative work, and what it says is that the park comprises the land in those two sub-districts within the boundary shown on the map appended to the decree. It names no islands. Not one.
So Tambon Koh Mak appearing in the title establishes that something in that sub-district is inside the park. It does not establish that Koh Mak island is. And there is a candidate that would satisfy the decree without the island: the Mu Ko Rang group, which the Tourism Authority of Thailand describes as expressly within Mu Ko Chang National Park and as hosting a park ranger unit, lies in the same sub-district about 6 km west of Koh Mak. TAT’s own phrasing treats Koh Mak as the landmark you measure Koh Rang from, not as park territory.
That is an argument. It is not a finding, and we are not dressing it up as one. Settling it needs the appended map or the department’s boundary data, and both were beyond us: the decree is a scan and the department’s park servers were unreachable. A Council of State opinion from 2547 on building a waste plant in the park repeats the same two sub-districts and the same total area of about 406,250 rai, and likewise lists no islands.
Practical consequence: do not accept anyone’s assurance on this, in either direction. If you are looking at a plot, a lease or a build here, get the boundary confirmed in writing by the Trat Land Office and by the national park before money moves. Where the park fee does apply in Mu Ko Chang, the band-2 rate under the December 2021 regulation is 200 baht for a foreign adult and 100 for a foreign child, against 40 and 20 for Thai visitors.
Power, water and the 2015 cable
Koh Mak’s electricity story is one of the better-documented things about the island, because the Public Debt Management Office published an evaluation of the project that delivered it. The Koh Mak leg of the Provincial Electricity Authority’s submarine cable is 22 kV, 120 sq mm, over 17 circuit-km, running from Ao Salad on Koh Kood to Ao Nid on Koh Mak. Cabinet approved the scheme on 13 February 2012; supply commenced 18 May 2015 per the evaluation, while PEA’s own announcement dates the switch-on ceremony to 4 August 2015. We cannot reconcile those two dates — most likely energisation against official opening — so both are here.
The number that shows what changed is the unit cost. Before the cable, PEA ran the island on 0.960 MW of diesel at a production cost of 8.75 baht per unit. After it, 3.02 baht. That is the difference between an island where air conditioning is a luxury and one where it is ordinary, and it is why almost everything built on Koh Mak in the last decade postdates 2015.
Water did not follow. The Trat provincial data catalogue states that the Provincial Waterworks Authority’s Trat branch serves Mueang Trat, Laem Ngop, Khao Saming and Bo Rai; Amphoe Koh Kood, which contains Tambon Koh Mak, appears under neither that branch nor Khlong Yai. The island is on village waterworks run by the sub-district administration, which in September 2025 sent a delegation to the PWA’s Chonburi branch to learn how to manage them better. On internet we have nothing official at all and are printing nothing.
What we could not confirm
- Whether Koh Mak island is inside Mu Ko Chang National Park. The decree draws its line on an appended map we could not read. The single most important open item on this page.
- Who owns the island. The private-family story is repeated everywhere and sourced nowhere official. Reported land area varies between about 9,000 and 9,500 rai and the number of owning families between one and five. No government source states any of it.
- The sub-district’s land area, village count and household count. These are in the sub-district administration’s own development plan, which we could not retrieve.
- Laem Sok to Koh Mak crossing time and fare, and the Koh Chang to Koh Mak leg. Boonsiri publishes timetables as images; the province publishes times without fares.
- The eight-point island charter often quoted as banning styrofoam and capping rental motorcycles. No official host, no ordinance, no Gazette notice. Voluntary, as far as we can tell.
- Internet and mobile coverage. Nothing from NBTC or any operator naming Koh Mak.
- Immigration. Trat provincial immigration’s own site refused us, so we cannot say whether any service point exists on the island. Assume a mainland trip for ninety-day reporting unless you have confirmed otherwise.
- The current registered population from the Department of Provincial Administration. The 436 figure above is from a Trat Immigration table published in April 2024; the DOPA statistics portal was unreachable.
Frequently asked questions
By speedboat, from two mainland piers or from Koh Kood. The Trat provincial government's own advisory lists services to Koh Mak from Krom Luang Chumphon pier at Laem Ngop at 10:00 and 16:00, and from Laem Sok pier at 11:30, 12:30, 15:00 and 16:00 - all described as speedboats, with no fares or durations published. From Koh Kood the hop is thirty minutes: Boonsiri publishes it at 400 baht and Koh Kood Express at 500 baht, the latter landing at Ao Nid on Koh Mak. Koh Kood Express also sells a combined boat and minivan run to Suvarnabhumi, leaving Koh Mak at 09:00 and arriving 17:00 for 1,100 baht. There is no airport on the island; the nearest is Trat (TDX) on the mainland. We deliberately do not print a Laem Sok crossing time or fare here - Boonsiri publishes its timetables as images we could not read reliably, and the one automated reading we got was internally inconsistent. Ask the operator.
Nobody we could reach is able to say, and that matters more here than on most islands. The 1982 royal decree is titled as covering the land of Koh Chang and neighbouring islands in Tambon Koh Chang and Tambon Koh Mak, and its section 3 fixes the park boundary by a map appended to the decree - it enumerates no islands at all. So the appearance of Tambon Koh Mak in the title proves only that some land or sea in that tambon is inside the line, not that Koh Mak island is. There is a plausible explanation that does not put the island in the park: the Mu Ko Rang group, which the Tourism Authority of Thailand describes as expressly within Mu Ko Chang National Park and the site of a park ranger unit, also lies in Tambon Koh Mak, about 6 km west. TAT positions Koh Rang relative to Koh Mak as an external landmark. That is inference, not proof. If you are buying or leasing on this island, put the boundary question to the Trat Land Office and to the park in writing.
The island is widely described as being largely in private family hands, dating to a single owner who took the island in 1904 - unusual for a Thai island, and the reason it is often said to have avoided the development pattern of its neighbours. We could not confirm any of it from a government source. Nothing on a Thai government site, no Royal Gazette entry, no provincial record and nothing from the sub-district administration states who owns what. The claim appears on a ferry operator's own island page and on a public research body's community wiki, and the reported details do not agree with each other: the island's area is variously given as about 9,000 or 9,500 rai, and the number of owning families as one or as five. We are recording that the claim exists and that we could not verify it, rather than repeating a version of it as fact.
A sub-district health promoting hospital with no inpatient beds. The Ministry of Public Health's facility registry lists Koh Mak Sub-district Health Promoting Hospital at 32 Moo 1 with beds in actual use recorded as zero. That is the bottom tier of the Thai public system: primary care, staffed by nurses and health officers, no admissions. Anything needing a bed means a boat. The referral chain runs to the mainland and ultimately to the provincial hospital in Mueang Trat, which the King renamed Phra Piya Maharat Hospital by royal grant with effect from March 2026 - it was Trat Hospital until then - and which the registry shows as a general hospital at service level S with 395 beds. Nearer at hand, Koh Kood Hospital is thirty minutes away by boat but is itself only a level-F3 community hospital with seven beds in use. We found no recompression chamber anywhere in Trat province, and we could neither confirm nor rule one out.
Power yes, since 2015. Water no. The Public Debt Management Office's evaluation of the Provincial Electricity Authority's submarine cable project records the Koh Mak leg as 22 kV, 120 sq mm, over 17 circuit-km, part of a scheme approved by cabinet in February 2012 with supply commencing 18 May 2015. The figure that shows what it changed: before the cable, Koh Mak ran on 0.960 MW of PEA diesel at a unit production cost of 8.75 baht, and after it the cost fell to 3.02 baht. PEA's own announcement describes the cable running from Ao Salad on Koh Kood to Ao Nid on Koh Mak and dates the switch-on ceremony to 4 August 2015, which does not match the PDMO's 18 May - most likely energisation against official opening, but we cannot reconcile them, so both are on the record here. On water, the Trat provincial data catalogue states that the Provincial Waterworks Authority's Trat branch serves Mueang Trat, Laem Ngop, Khao Saming and Bo Rai. Koh Kood district appears under neither branch. Koh Mak runs on village waterworks administered by the sub-district administration, which visited the PWA's Chonburi branch in September 2025 to take back knowledge on managing them.
It has real sustainable-tourism recognition, and the specific bans people repeat are not law as far as we can establish. DASTA - the state agency for designated sustainable tourism areas - records Koh Mak's selection as one of Green Destinations' Top 100 sustainable destinations for 2022 and a 2023 Green Destinations Story Award in the Governance, Reset and Recovery category. The awarding body there is an international NGO, with DASTA driving it on the Thai side. The island sits inside the Koh Chang and linked-areas special area declared on 24 September 2004. What we could not find on any government site is the eight-point island charter that is widely quoted as capping rental motorcycles at seventy per cent of room count and barring styrofoam and tourist vehicles from the ferry. No ordinance, no provincial order, no Gazette notice. Treat it as a voluntary agreement among operators, which is a real thing and worth respecting, but not as a regulation you could be fined under.
Related guides
- Koh Kood — the other island in this district, thirty minutes away, with the district office and the hospital.
- Koh Chang — the province’s big island and the one with the car ferry.
- Cost of living in Koh Chang — the nearest budget tables we hold for this coast.
- Island living in Thailand — how the islands differ on the things that decide a move.
- National parks in Thailand — the fee bands and what the 2019 Act changed.
- Lease registration checklist — what has to be registered, and where, before a long lease means anything.
- DTV visa and retiring in Thailand — the two routes most island long-stayers ask about.
- Explore Thailand — the section this guide sits in.
436 residents, and a boundary question worth settling before you buy
Small-island property in Trat rewards the people who ask the Land Office first. Start with what is actually listed, then get the paperwork checked.
Sources & References
- Royal decree of 31 December 1982 declaring the land of Koh Chang and neighbouring islands, in Tambon Koh Chang and Tambon Koh Mak, Laem Ngop district, Trat, a national park - hosted in the Department of National Parks' own file drawer at the Official Information Commission. Section 3 fixes the park boundary by the map appended to the decree and enumerates no islands
- Department of National Parks - Mu Ko Chang National Park: Thailand's 45th national park, declared 31 December 1982, spanning Koh Chang and Koh Kood districts in Trat, about 650 sq km of which 503 sq km is sea
- Department of National Parks - the national park fee bands under the DNP regulation of 9 December 2021, in force 7 June 2022. Mu Ko Chang sits in band 2: Thai child 20 and adult 40, foreign child 100 and adult 200 baht
- Tourism Authority of Thailand - the Mu Ko Rang island group, expressly within Mu Ko Chang National Park, about 6 km west of Koh Mak and the site of a park ranger unit
- Public Debt Management Office - project evaluation of the Provincial Electricity Authority's submarine cable to Koh Kood and Koh Mak: a 22 kV system, the Koh Mak leg 120 sq mm over 17 circuit-km, cabinet approval 13 February 2012, supply commencing 18 May 2015, completion 25 December 2018; before it, Koh Mak ran on 0.960 MW of PEA diesel generation at a unit production cost of 8.75 baht, which fell to 3.02 baht after the cable
- Trat provincial government data catalogue - the Provincial Waterworks Authority's Trat branch serves four districts, Mueang Trat, Laem Ngop, Khao Saming and Bo Rai. Amphoe Koh Kood, which contains Tambon Koh Mak, appears under neither Trat branch nor Khlong Yai branch
- Provincial Waterworks Authority - the Koh Mak sub-district administrative organisation's study visit to the PWA Chonburi branch, 18 September 2025, to take back knowledge and technology for managing the island's village waterworks
- Trat Provincial Immigration - published population table for the province by sub-district, April 2024: Tambon Koh Mak 219 male, 217 female, 436 in total
- Koh Mak Subdistrict Administrative Organisation (อบต.เกาะหมาก) - the local authority for the island, at 34/2 Moo 1, Wong Siri Road, Tambon Koh Mak, Amphoe Koh Kood, Trat 23120, telephone 039-510748
- Ministry of Public Health health-facility registry - Koh Mak Sub-district Health Promoting Hospital (โรงพยาบาลส่งเสริมสุขภาพตำบลเกาะหมาก), facility code 02175, at 32 Moo 1, Tambon Koh Mak, Amphoe Koh Kood, with zero beds in actual use
- Ministry of Public Health health-facility registry - Phra Piya Maharat Hospital (โรงพยาบาลพระปิยมหาราช), the Trat provincial hospital, formerly named โรงพยาบาลตราด, a general hospital at service level S with 395 beds in actual use
- Office of the Basic Education Commission school information system - Ban Koh Mak School (Sathit Sutthiwong), SMIS code 23010113, at 32/1 Tambon Koh Mak, Amphoe Koh Kood, Trat 23120, under Trat Primary Educational Service Area 1, teaching kindergarten 2 and 3 and Prathom 1 to 6, total enrolment 83 as of 10 June 2026
- Designated Areas for Sustainable Tourism Administration (DASTA) - the Koh Chang and linked-areas special area, declared 24 September 2004 across six districts of Trat, and Koh Mak's selection as one of Green Destinations' Top 100 sustainable destinations for 2022 and a 2023 Green Destinations Story Award in the Governance, Reset and Recovery category
- Government Public Relations Department, Trat - the province's published island sailings: speedboats to Koh Mak from Krom Luang Chumphon pier at Laem Ngop at 10:00 and 16:00, and from Laem Sok pier at 11:30, 12:30, 15:00 and 16:00
- Koh Kood Express Ferry - the operator's own schedule for the Koh Kood to Koh Mak legs, calling at Ao Nid on Koh Mak, at 500 baht
- Boonsiri High Speed Ferries - the operator's own seasonal timetables, published as two sheets, high season 1 January to 31 May 2026 and low season 4 June to 30 September 2026, and the Koh Kood to Koh Mak leg at 30 minutes and 400 baht
- Thai Meteorological Department - the monsoon calendar: the southwest monsoon covers Thailand from about mid-May to mid-October, and the northeast monsoon from about mid-October to mid-February
Primary and official sources are cited above. Government rules, fees and procedures in Thailand change over time and vary by office; always confirm current requirements with the relevant authority before relying on them. BAANLYY never takes paid placement in editorial content.
