Cambodia Visa for American Students: The ES Extension Path

Which eVisa class to enter on: Business, not Tourist

This is the decision that matters, and you make it before you fly. American students should enter Cambodia on the Business eVisa ($90 USD all-in), not the Tourist eVisa ($80 USD all-in). The $10 difference is the single most important $10 in your whole study-trip budget, because it decides whether you can convert to the ES extension at all.

The reason is simple. Only the Business eVisa (Type-E) can be extended in-country. The Tourist eVisa cannot — and the old Tourist auto-extension that used to give travelers a second 30 days ended in November 2025. So a Tourist eVisa now gives you exactly 30 days, full stop, with no legal path to stay longer. For a student, that is a dead end. You would burn your 30 days, then have to fly out and re-enter, and you still could not convert to ES.

A short program — a two-week Khmer-language intensive, a one-week field study, a brief research visit — that genuinely wraps inside 30 days can run on the Tourist eVisa, since you will leave before any extension is needed. But the moment your study stay touches the 30-day mark, or there is any chance it might, the Business eVisa is the only correct choice. Most American students enrolling for a semester, a language year, or a full degree should enter on the Business eVisa without a second thought.

The Business eVisa application is the same short, ten-minute online flow as the Tourist one — passport, photo, email, payment — and it does not require any proof of enrollment at the apply stage. You do not need your acceptance letter to get the eVisa; you need it later, for the ES conversion. If you want the full side-by-side on the two classes, the Cambodia tourist vs business visa for Americans comparison lays out every field.

How the ES student extension works in-country

Once you have landed in Cambodia on the Business eVisa, the ES extension is arranged through a Cambodian immigration agent — not at a government counter you visit yourself, and not online from the US. Most American students use an agent in Phnom Penh or Siem Reap, often one their university or language school already works with. The agent takes your passport, lodges the ES extension paperwork on your behalf, and returns your passport stamped a week or two later.

The "ES" label marks the extension as the student category, as opposed to the EB (business/general) category that most working long-stayers use. Functionally, the lengths and renewal mechanics are the same: extensions are available in 1, 3, 6, and 12-month blocks, and they are renewable, so you can stack them to cover a full academic year or a multi-year degree. The 12-month extension is multi-entry, which matters if you plan to fly home for the US summer break or pop out to Bangkok or Singapore mid-year and come back.

What the agent needs from you for the ES sub-type, beyond the standard extension paperwork, is proof that you are actually studying — most commonly an enrollment letter or acceptance letter from your Cambodian university, language school, or program, on the institution's letterhead. Some schools issue this as a matter of course for international students; others need a nudge. Ask your program's international-student office for it as soon as you accept your place, so it is in hand the week you arrive.

Timing matters. Start the ES extension paperwork at least two weeks before your initial 30-day Business eVisa stay expires. Agent processing typically runs 7 to 14 days, and cutting it close risks an overstay — Cambodia charges $10 USD per day for overstaying, payable in cash at the airport on exit, and a long overstay can complicate future visa applications. Getting the enrollment letter ready before you fly is the single best thing you can do to keep the ES conversion smooth.

The ES (student) and EB (business/general) extensions sit side by side in the same system, and students sometimes find themselves choosing between them depending on what their school can document. The Cambodia EB visa extension explained for Americans walks through the general long-stay extension in detail, which is useful background even when ES is the route you ultimately take.

Mapping common American student trips to the right path

The right combination of eVisa class and ES extension length depends entirely on how long you are studying. Here is the working map we use with US students, based on the programs we see most often.

• Short language intensive or field study under 30 days — e.g. a two-week Khmer-language course or a one-week academic field trip. The Tourist eVisa ($80 USD) covers it, since you leave before any extension is needed. No ES conversion required.
• Semester abroad, roughly 3 to 5 months — e.g. a Boston student on a fall-semester placement at a Phnom Penh university. Enter on the Business eVisa, then convert to a 3-month or 6-month ES extension. The 6-month block usually covers a full semester plus exam period with room to spare.
• Full academic year, language immersion year, or gap year — e.g. a recent US graduate doing a year of Khmer study in Siem Reap. Enter on the Business eVisa, then take a 12-month ES extension. It is multi-entry, so you can fly home for the holidays and return.
• Multi-year degree at a Cambodian university — e.g. an American enrolled in a full bachelor's or master's program in Phnom Penh. Enter on the Business eVisa, then renew the ES extension year by year. Most degree students settle into renewing 12-month ES blocks annually.
• Research fellowship or exchange with mixed study and unpaid work — e.g. a US doctoral researcher affiliated with a Cambodian institution for eight months. Business eVisa entry, then a 6-month or 12-month extension; whether it is filed as ES or EB depends on what your host institution documents.

The pattern is consistent. If your stay is under 30 days, the Tourist eVisa is fine. If it is anything longer — which describes nearly every genuine study program — enter on the Business eVisa and convert to ES once you are in-country with your enrollment letter. Choosing the extension length up front, rather than defaulting to short blocks, saves both money and repeat trips to the agent.

Students whose programs blur into volunteering, teaching, or unpaid placements have a closely related path worth understanding. The Cambodia visa for volunteering and teaching for US citizens guide covers how those trips map onto the same Business eVisa and in-country extension system, which often overlaps with what student-researchers and exchange participants are doing on the ground.

Documents you need, and the mistakes that strand students

The eVisa application itself asks for the same short pack as any other Cambodia eVisa — five items, all of which most American students already have. The school paperwork comes into play only later, at the ES conversion stage.

• US passport — at least 6 months validity from your planned date of arrival in Cambodia, with at least one full blank page for the entry stamp. For a multi-year degree, renew early if your passport expires mid-program.
• Digital passport-style photo — plain white background, taken in the last 6 months, no glasses, no hats, no smile, neutral expression. JPEG, under 2 MB.
• Clear scan or phone photo of your passport bio page — both edges visible, no glare on the laminate, all text legible.
• Working email address — the approval PDF lands here, so use a personal inbox that accepts PDF attachments, not a university account that may expire or filter attachments.
• Payment method — Visa, Mastercard, American Express, PayPal, Apple Pay, or Google Pay.
• Enrollment or acceptance letter from your school — NOT needed for the eVisa, but essential for the ES extension later. Get it from your program's international-student office before you fly.

Now the mistakes. The single most common one is entering Cambodia on the Tourist eVisa because it is $10 cheaper, then discovering on day 25 that it cannot be extended and the auto-extension is gone. That student is stuck: their only options are to leave and re-enter on a fresh Business eVisa, or to abandon the stay. The fix is free and trivial — choose the Business eVisa before you book.

The second mistake is arriving without the enrollment letter and assuming the school will produce one on demand. Some institutions are slow, some require an in-person request, and a missing letter can stall your ES conversion right up against your 30-day deadline. Request it in writing the moment you accept your place. The third is leaving the extension to the last minute — start the agent paperwork at least two weeks out, because 7 to 14 days of processing against a hard 30-day clock leaves no margin for a slow week at the agent.

A note on family and dependents: if you are bringing a spouse or child while you study, each person needs their own eVisa and their own extension — there is no family ES application, no shared file, and no dependent rider on a student's extension. If you are still unsure whether your trip fits the student box at all, the quick guide on which Cambodia visa you need as a US citizen walks you to the right class in a minute.

Arrival, e-Arrival, and putting it together

Arrival as a student is identical to any other Business eVisa arrival. Print two copies of your eVisa approval PDF — one for entry, one for exit — and carry your US passport with at least 6 months validity. Have your e-Arrival QR code saved to your phone with a screenshot for offline access, in case airport Wi-Fi is slow. Open airports for US arrivals are KTI (Phnom Penh — the new Techo International Airport, which replaced the old PNH on 9 September 2025), SAI (Siem Reap-Angkor), and KOS (Sihanoukville).

The immigration officer may ask the purpose of your visit. "Studying" or "enrolled at a university in Phnom Penh" is a perfectly standard answer on a Business eVisa — the Business class is the foundation the ES student extension builds on, so there is nothing awkward about declaring study at the desk. Land entry for students is realistic only from Vietnam at Bavet or from Laos at Tropaeng Kreal; all seven Thailand-Cambodia land borders have been closed since June 2025, so a Bangkok-overland plan does not work in 2026.

Put together, the path for an American student is short to describe and easy to get right: enter on the Business eVisa ($90 USD all-in, approved in 3 business days, delivered as a printable PDF by email), get your enrollment letter in hand, then convert to the ES extension in-country through an immigration agent for the length your program needs. The US Embassy in Phnom Penh publishes current entry and local-conditions guidance that is worth a five-minute read before you fly.

Next steps and related reading for US students: apply for your Cambodia eVisa when you are ready to lodge, keep the umbrella hub as your single canonical reference for cost and documents, read the Business eVisa deep dive for the class that underpins every study stay, and use the quick decision guide if you are still unsure which class fits your program.