What are CoE, I-20, CAS? "Key" documents to apply for a visa

🔄 Cập nhật lần cuối: 08/10/26

When applying to study abroad, you will hear a lot about CoE, I-20, and CAS. So what are CoE, I-20, CAS? These are documents issued by the school (or immigration agency) to confirm that you have been accepted and are eligible to apply for a student visa. Without them, it is almost impossible to apply for a visa. This article explains each type by country, when to receive it and what to check.

Why are they called "key" documents?

The Offer Letter only indicates that the school agrees to accept you. To apply for a visa, immigration authorities need an official confirmation, tied to the country's international student management system. This document is usually only issued when you have an unconditional offer, accept the offer and complete the required deposit and insurance. See more articles Conditional and unconditional offer letters.

CoE (Confirmation of Enrolment) – Australia

CoE is an electronic admission confirmation issued by a CRICOS registered school. Each course (including English and preparatory courses in the package) has its own CoE code. You enter the CoE code when applying for a subclass 500 student visa.

• When to receive: after accepting the offer, paying tuition/deposit and usually OSHC insurance.
• Need to check: full name, date of birth, course code, start and end date, tuition.

Details about visas are in the article Australian student visa subclass 500 and about insurance in the article OSHC study abroad health insurance.

I-20 – USA

Form I-20 (Certificate of Eligibility for Nonimmigrant Student Status) is issued by a school approved by SEVP for F-1 (or M-1) students. The I-20 lists the program of study, start date, estimated one-year expenses and funding source, with SEVIS code.

• When to accept: after matriculation and submitting financial documents to the school.
• Used to: pay SEVIS I-901 fee, declare DS-160, visa interview, enter the US.
• Note: sign the I-20, bring the original to the interview and upon entry; New students may not enter the country earlier than 30 days before the program start date.

See the full process in the article F-1 US student visa.

CAS (Confirmation of Acceptance for Studies) – English

CAS is an electronic reference code issued by a licensed student sponsor in the UK. CAS accounts for the majority of points in the UK student visa scoring system and contains course information, tuition fees, amounts paid, and school documents used for admission.

• When to receive: after receiving an unconditional offer, depositing and completing the school's inspection.
• Note: apply for visa within 6 months of receiving CAS; The amount of financial proof required is calculated according to the remaining tuition fee recorded on the CAS.

See article UK student visa: CAS, points and financial proof.

Other countries: Canada, Japan, Korea, Germany

• Canada: Letter of Acceptance from DLI school, with PAL/TAL if required. See Canadian study permit.
• Japan: COE (Certificate of Eligibility) issued by the Japanese immigration agency, usually submitted by the school. Note: Japan's COE is completely different from Australia's CoE. See Japan student visa.
• Korea: admission notice (invitation letter) from the school along with school documents as required by the consulate.
• Germany: admission letter (Zulassung) or preparatory invitation letter, with APS certificate for Vietnamese students.

Comparison table of CoE, I-20, CAS

The course start date on the CoE, I-20 or CAS is an important basis for choosing a flight date and avoiding violating immigration regulations. VeDuHoc has more than 30 Bookers to hunt multi-carrier tickets, check transit visas according to itinerary, optimize checked baggage and 24/7 support. See air tickets to study abroad and Identification documents for air travel.

Frequently asked questions

Are CoE and COE the same?

Are not. Australia's CoE is a confirmation of admission issued by the school; Japan's COE is a certificate of residence status issued by the Japanese immigration agency. The two documents only have the same initials.

What if the information on the I-20 is wrong?

Contact the school's international student officer (DSO) to edit and issue a new I-20 before the visa interview.

If I change my admission date, can CoE and CAS still be used?

Usually must be reissued or updated by the school. If the visa has already been issued, ask the school and check the immigration agency's regulations regarding changes.

Having CoE, I-20, CAS is sure to have a visa?

Are not. This is a necessary condition; The visa agency still considers finances, educational purposes, health and other requirements.

Understanding CoE, I-20, CAS helps you understand the correct order of documents and avoid wasting time. Once you have the "key" documents and visa, contact VeDuHoc via hotline/Zalo 090.1800.918 to book tickets suitable for the admission schedule.

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