What is Activation code?
The code is normally single-use and should be treated like a password. Never post your QR code or activation code publicly.
The activation code tends to get overlooked because it sits behind the familiar-looking QR code, but technically it is the real key that lets a phone download a profile — not the QR image itself. When a QR code is scanned, what the phone actually reads out is an SM-DP+ server address paired with this activation code, and the phone then sends the code to that server for checking before it is allowed to download the actual profile. Without a valid code, the whole process stops at the very first step.
This page is for anyone about to install an eSIM for the first time and wanting to understand what this code is, why it matters, and what to watch for so installation goes smoothly. It covers how the code works, common mistakes, and how to treat it as safely as any other important password.
What the activation code actually is
The activation code is a string of letters and numbers generated specifically for one particular eSIM profile. It acts as proof that the phone requesting the download genuinely has the right to do so. The SM-DP+ server checks this code every time, and only if it matches the profile waiting to be downloaded does the server allow the process to continue.
The code is generally not designed for a person to memorise or retype easily, because the more complex it is, the harder it is for anyone else to guess or forge. That is why the most convenient way to pass it along is embedding it in a QR code to scan, rather than typing every character by hand — although typing it manually remains possible for situations where scanning is not convenient.
Why this code looks longer and more complex than familiar codes
Anyone used to a physical SIM's simple four-digit PIN may be surprised at how long the activation code is, mixing letters and numbers. That length and complexity is not there to be difficult for its own sake — it exists so the number of possible codes is large enough that guessing the right one by chance is next to impossible.
How the activation code pairs with the SM-DP+ address
Manual installation needs two pieces of information working together: the SM-DP+ server address, which says where to reach out to, and the activation code, which says exactly which profile to request. The two have to match precisely — enter the right address with the wrong code, or the right code with the wrong address, and installation fails either way.
When a QR code is scanned instead of typing manually, the phone extracts both pieces of information from that same image automatically, so there is no risk of a mistyped character or a mismatched pair. That is why scanning is usually recommended as the primary method whenever it is possible, with manual entry kept as a fallback for when scanning is simply not convenient.
Where this code can be found
The activation code is usually delivered together with the QR code on the order page or in an order-confirmation email, and it is sometimes shown as plain text separately from the QR image too. For cases requiring manual entry, the important thing is keeping this information somewhere accessible while travelling, since installation sometimes has to happen before a fully working internet connection is available.
Why the code is normally single-use
The activation code is generally designed to be tied to a single profile download, since one eSIM profile is intended for installation on one device only — not for handing around to several devices to use at once. Once the code has been used and the profile downloaded successfully, the system usually rejects any further attempt to use that same code again from a different device.
This limitation exists mainly for security reasons. If a single code could be reused an unlimited number of times, anyone who saw it could hijack access to that profile for themselves. Restricting it to one use significantly reduces that risk, even though it also means that if installation goes wrong or the profile gets deleted afterwards, the same original QR code usually cannot be used to install it again.
If the code has already been used or has expired
If the phone reports that the code has already been used or has expired on a first attempt at installation, the first thing to check is whether that code was already scanned or entered previously — for instance, accidentally scanning the same email's QR code twice, in a situation where the first attempt actually succeeded without it being obvious, or opening the same email from more than one device.
If it is confirmed that no earlier installation ever succeeded, yet the code is still rejected, contact the team on LINE or by email with the order number and the exact message the phone shows. The team will check that code's status in the system, which may lead to issuing a fresh profile if that genuinely turns out to be necessary.
Treat this code like a password
Because the activation code is what directly grants access to a profile, it deserves the same care as any important password — not something to be shared around casually as ordinary information. Anyone who sees the QR code or the activation code before actual installation has the chance to install it on their own device first, ahead of the real owner ever getting the chance to use it.
A simple rule that always applies: if a bank account password would not be shared publicly, an eSIM's QR code and activation code should be treated the same way. That means no sharing in public groups, no forwarding through insecure chats, and no screenshotting and posting to social media without deliberately hiding this part of the image.
Manual entry steps when scanning is not possible
- 1Open the add a mobile data plan menu manuallyThe location of this menu differs by device manufacturer and operating-system version, so check our own installation guide alongside that specific model's own manufacturer instructions.
- 2Enter the SM-DP+ address exactly as receivedCopy or type it to match exactly character for character, including letter case if it differs, since a single wrong character in the address prevents the connection from succeeding.
- 3Enter the activation code exactly as receivedWatch for easily confused characters, such as zero versus the letter O, or the number one versus a lowercase L, since a single mistyped character means the code no longer matches what the server is waiting to verify.
- 4Confirm and wait for the phone to finish downloading the profileDo not lock the screen or switch apps while it downloads, since that can interrupt the process partway through, and the code may then count as used even though installation never actually completed.
In short, the activation code is a small piece that carries a lot of weight in the whole process, since it is what decides which device gets the right to download the profile. Treating it carefully from the moment it is received through to well after installation succeeds helps keep both the first installation and the profile's ongoing security exactly as they should be.
The activation code compared with similar-looking codes
| Code | What it does | Should it be kept secret |
|---|---|---|
| Activation code | Authorises downloading the profile from the SM-DP+ server | Yes, keep it as secret as a password |
| SM-DP+ address | States which server to connect to | Not as sensitive as the activation code, but must be entered accurately |
| EID | Identifies the phone's own eSIM chip, not tied to any one profile | Not as sensitive as the activation code, though still not worth publishing needlessly |
Common mistakes around the activation code
| Common misunderstanding | What to understand instead |
|---|---|
| Deleting a profile and rescanning the same QR always reinstalls it | The code is normally single-use, and deleting it usually leaves the same QR unable to reinstall it |
| Sharing the QR in a trusted friend group chat is fine | Anyone who sees it before real installation can scan and use it first |
| The activation code and the SM-DP+ address are the same thing | They are two separate pieces of information used together; both must be correct for installation to succeed |
| One small typo surely will not cause a problem | A single wrong character means the code no longer matches what the server expects, and the connection fails |
The activation code when buying again or buying a new plan
Every new plan bought, whether for the same destination as before or a new one, always comes with its own fresh activation code — not a reuse of the code from an earlier order. Each profile is tied to its own specific code from the outset, so keeping an old code from a previous order around for a new profile serves no purpose and usually only creates confusion about which code belongs to which order.
To reduce confusion, it helps to delete or set apart the QR code and code from an old order that has already installed successfully, keeping it separate from a new order's own. Removing an old email from a frequently opened list, or keeping each trip's screenshots in its own folder, for example. That way, when scanning or entering manually for the next trip, the wrong set does not get picked up by mistake.
Recognising a scam message that asks for this code
Because the activation code has value on its own, it is a target scammers may impersonate someone to ask for — claiming to be support staff trying to help fix a problem, or claiming to be a security check that needs the code confirmed first. Messages like this usually arrive with urgency, pressuring a quick reply without leaving time to verify anything properly first.
Our own team only communicates back through LINE at https://lin.ee/skDPoNx or email at esimonline.asia@gmail.com, and would never ask for the activation code or QR code to be sent through any other channel outside a conversation you started yourself on these. If a message arrives from any other channel claiming to be us, treat it with suspicion first and confirm directly through the channels named here instead.
If the code genuinely needs passing to someone else to install
Sometimes the person buying the plan is not the one who will actually activate it on a phone — buying for a family member who is not comfortable doing it themselves, say. In that case the code or QR genuinely needs passing along, but it should go only through a secure, direct one-to-one conversation with that person specifically — a private chat with just them, not a group chat that includes anyone else.
After it has been sent and installation succeeds, delete the message containing the code from both sides of the chat history if possible, to reduce the chance of it lingering somewhere someone else could later access — even though the code has already been used and cannot install again. Deleting it afterwards is still a good habit for overall security.
A checklist before using the activation code
- Keep a copy of the QR code and the activation code somewhere reachable even without internet
- Never post or share this QR code and activation code publicly, for any reason
- Confirm no earlier installation ever succeeded before suspecting the code itself is faulty
- Enter the SM-DP+ address and the activation code exactly character for character if installing manually
- Message the team on LINE or by email if the code is rejected despite no earlier successful installation
Časté otázky
Are the activation code and the QR code the same thing?+
No. The QR code is simply an image that packages the SM-DP+ address and the activation code together. Scanning it is a convenient way to feed both pieces into the phone at once, instead of typing them manually.
Why is the activation code normally single-use?+
Because one eSIM profile is intended for installation on a single device only. Limiting the code to one use helps prevent anyone else who sees it from installing it again on their own device.
If an old profile was not deleted before moving to a new phone, can the same code install it on the new phone?+
Generally not, since the code is usually counted as used from the first installation onward. If moving to a new phone is genuinely needed, contact the team on LINE or by email first to ask about the right approach for that situation.
If a screenshot showing the QR code was accidentally posted on social media, what should be done?+
Delete that post immediately and contact the team on LINE at https://lin.ee/skDPoNx or email esimonline.asia@gmail.com as soon as possible to report it. The team will help check whether that profile has already been used.
If typing the activation code manually results in a rejection message, what should be checked first?+
Check that every character was entered correctly in both the SM-DP+ address and the activation code, watching especially for easily confused characters such as zero versus the letter O. If it still fails, try scanning the QR code instead if that option is still available.
Does the activation code have an expiry date?+
The code can expire in some cases, depending on the network operator that issued the profile. If a message shows the code has expired, contact the team on LINE or by email with the order number to check and get help.