For international students aiming to study in the UK, the CAS letter (Confirmation of Acceptance for Studies) is the foundation of the entire visa application process. This official document, issued directly by your chosen university, confirms your admission and provides all the details UK Visas and Immigration (UKVI) requires to process your student visa. Without a valid CAS number, you cannot move forward with your visa application.
To make the journey smoother, students should understand how the CAS process works from required documents to timelines because even small errors can lead to delays or rejections. According to recent UKVI guidance, incomplete or mismatched information is one of the most common reasons applications are put on hold. With careful preparation, you can avoid these pitfalls and focus on what really matters: starting your academic journey in the UK.
In this guide, we’ll break down everything you need to know about the CAS letter: its meaning, why it’s important, what details it contains, and how to obtain one. We’ll also cover related topics such as the CAS Shield system, combined CAS numbers, deadlines, and the steps to take immediately after receiving your letter.
What Is the Full Form of CAS?
The term CAS stands for Confirmation of Acceptance for Studies. It is an official document issued by a UK university or higher education provider licensed by UKVI, not by UCAS. While UCAS handles undergraduate applications in the UK, only your chosen institution can generate a CAS number for visa purposes.
For international students, the CAS is more than just an acceptance confirmation it is a unique electronic reference number linking your admission details to the UKVI system. Without it, you cannot begin the Tier 4 or Student Route visa process. According to the UKVI 2025 update, each CAS is valid for six months before the course start date, ensuring students have sufficient time to prepare their visa application.
What Is a CAS Letter?
A CAS letter is a secure electronic document issued by a UK university after you have officially accepted your offer and met all conditions. Unlike the initial offer letter, the CAS confirms that the university has entered your details into the UKVI database, generating a unique CAS number linked to your student record.
This document is not just proof of admission, it is a vital requirement for your UK Student Visa application. Universities typically issue CAS letters only after verifying tuition fee deposits, academic transcripts, and English language qualifications. According to UKVI guidance, each CAS can only be used once and is valid for a specific course and institution. You must apply for your visa using the exact details provided in your CAS.
What Is Included in a CAS Letter?
Each CAS letter contains a detailed record of your student profile that the UKVI uses to verify your visa application. Key details include:
- Unique 14-digit CAS reference number linking your information to the immigration system
- University’s Sponsor Licence Number (SLN) and official address
- Your full name, passport details, and nationality
- Course title, start and end dates
- Confirmation of academic qualifications used for admission
- Tuition fees breakdown, paid amounts, and accommodation deposits
- English language proficiency scores (e.g., IELTS, TOEFL)
- ATAS clearance if your course requires it
Even small mismatches, like a spelling error or an incorrect date, can lead to delays or refusal. According to UKVI 2025 guidelines, over 20% of application errors stem from incorrect CAS details. Double-checking your CAS letter is one of the most important steps before applying for a visa.
What Is a Combined CAS Number?
A Combined CAS number is designed for students enrolled in more than one course at the same university. Instead of applying for separate visas, this single CAS allows you to apply for one student visa covering both programs.
This is particularly useful for students progressing from a foundation course to an undergraduate degree, or from a master’s program to a PhD. According to the UK Home Office, a Combined CAS demonstrates academic progression and continuity, which strengthens your visa application. Always confirm with your university if you qualify for one, as rules may differ by course type.
Importance of a CAS Letter
The CAS letter is critical for a UK student visa. It confirms your acceptance, allows UKVI to verify your identity, academic history, and course details. Errors in names, dates, or course information can cause delays or refusals.
Pro Tip: Review your CAS letter carefully and contact your university immediately if you spot discrepancies. This proactive step can save weeks of potential delays and ensures a smoother visa process.
How to Get a UK CAS Letter
Follow these steps to obtain your CAS:
Step 1: Apply and Receive an Offer
Submit applications to your chosen universities. Once accepted, your offer letter will include course details and, in some cases, require a partial tuition fee deposit.
Step 2: Access CAS Shield
Log in to the CAS Shield portal using your registered email. This online system allows you to submit all required information for your CAS.
Step 3: Upload Required Documents
- Colour scan of your passport
- Academic transcripts
- English proficiency certificates (IELTS, TOEFL)
- Proof of tuition fee payment
- ATAS certificate (if required)
Step 4: Submit and Await Your CAS
After submission, monitor your email for the CAS letter. Universities typically process applications in 1–2 weeks, though peak periods may take longer.
Pro Tip: Double-check all documents and information. Discrepancies can delay CAS issuance and visa approval.
What Is the CAS Shield?
The CAS Shield is an online portal simplifying CAS applications. Students securely upload all documents and provide personal and academic information.
Steps to use CAS Shield:
- Log in with your registered email
- Complete personal and course details accurately
- Upload essential documents (passport, transcripts, English certificates, tuition evidence)
Pro Tip: Verify all files for clarity and completeness to avoid delays. CAS Shield ensures information reaches the university correctly, making it a crucial step for obtaining your CAS letter.
Required Documents for the CAS Letter
International students must submit:
- Valid passport scan
- Academic transcripts
- English language certificates
- Tuition fee deposit proof
- ATAS certificate (if required)
Tip: Use PDF format and confirm legibility. Some universities may request additional documents. Accurate submissions increase CAS issuance speed and improve visa approval chances.
CAS Letter Processing Time
After submission, expect your CAS within 1–2 weeks. In some cases, processing may take 3–4 weeks. Monitor your email and UCAS notifications.
Key points for faster processing:
- Submit complete and legible documents
- Respond promptly to university requests
- Keep contact info updated in UCAS
According to UKVI, a CAS letter should not exceed 90 working days from application. Planning ahead ensures smooth visa processing.
Handling a Conditional Offer Letter
A conditional offer letter means you must meet certain requirements before officially starting your course. For international students, this usually involves:
- Achieving a higher English proficiency score
- Submitting pending academic documents
Steps to proceed:
- Review conditions carefully
- Fulfill requirements promptly
- Submit proof to the university
Meeting conditions converts your offer to unconditional, allowing you to obtain your CAS letter and proceed with your visa.
How the CAS Letter Is Issued
Once your admission is approved, the university emails a link to start the CAS process. By logging in, you can access your CAS statement.
Sometimes, you must request a CAS number and upload supporting documents:
- Bank statements
- Previous academic transcripts
- English test results
After submission, the university provides a secure link to download your CAS letter, ensuring you can apply for your student visa without delays.
CAS Letter Application Deadline
- From outside the UK: apply up to six months before course start
- From within the UK: apply up to three months before start
Apply early to avoid delays and check university-specific deadlines.
Next Steps After Receiving Your CAS Letter
After receiving your CAS:
- Apply for your UK student visa
- Ensure all visa application info matches the CAS letter
- Double-check passport number, course dates, tuition fees
Managing Multiple CAS Letters: How to Choose Wisely
If you receive multiple CAS letters:
- Only accept one CAS letter
- Compare courses, tuition, scholarships, location, and career opportunities
- Choose the most suitable CAS for your academic goals
FAQs About CAS Letters
How long does it take to get a CAS letter?
1–2 weeks typically; can take 3–4 weeks in peak periods.
Does a CAS letter guarantee visa approval?
No. It provides the information required to apply for a UK student visa.
Is a CAS letter the same as an acceptance letter?
Yes, but you still need a visa to start your course.
Can I get a CAS letter without a deposit?
Sometimes, but most universities require a tuition deposit.
Is there a fee for a CAS letter?
No direct fee; deposits are usually required. Check your university website.
Conclusion: The Critical Role of Your CAS Letter
A CAS letter is an essential document for studying in the UK. It is required to complete your student visa application and is used by UKVI to verify your eligibility.
To avoid delays or rejection:
- Double-check all details match your visa application.
- Ensure all required documents are accurate and submitted on time.
- Keep a copy for your records for future reference.
Treat your CAS letter with care, as it directly affects your visa approval and study plans in the UK. Being thorough and attentive at this stage can save you weeks of processing time and stress.
