Introduction
Recently, I noticed someone on the internet visiting a Taiwan Mobile store to replace their SIM card.
After work, I couldn’t wait to head to the store for a replacement. Here’s a detailed account of my experience and insights.
Why Replace the SIM Card?
Taiwan Star offers affordable, attractive low-cost plans, including a 188 TWD/month unlimited 4G plan (5.77 USD/month), which is hard to resist for those with long-term stationary work.
On July 27, 2022, the three major telecom operators announced that 4G and 5G users could activate LTE voice (Voice over LTE, VoLTE) without a monthly fee. On August 17, 2022, Taiwan Star also started offering VoLTE services.
VoLTE allows voice data transmission over LTE (i.e., 4G), providing lower call latency, less data bandwidth usage, and maintaining the connection without falling back to 3G or 2G during calls.
VoLTE includes a feature called HD Voice, which improves sound quality when both parties are on the same network. Currently, HD Voice is not supported across different carriers, but this may change with future integrations.
Additionally, when the three major carriers announced free VoLTE services, they also offered VoWiFi (Voice Over Wi-Fi / Wi-Fi Calling) without a monthly fee. This feature allows calls over a Wi-Fi network, with the following benefits:
- You can make calls without LTE, even in basements or on planes, wherever there is Wi-Fi.
- Call data uses Wi-Fi, so no extra data charges apply.
However, Taiwan Star has not yet announced the availability of this feature. With the merger of Taiwan Star and Taiwan Mobile, this has become a focus. Now, Taiwan Star (Taiwan Mobile TS) users can visit a store to replace their SIM card and enable VoWiFi.
Preparation for SIM Card Replacement
- Two forms of ID (ID card + Health Insurance Card, or Driver’s License)
- Phone (to receive verification SMS on-site)
- If processing on behalf of someone, the phone owner’s stamp is needed.
SIM Card Replacement Process
The entire process can be completed in about 5 to 10 minutes if there is no one else waiting.
Beforehand, I inquired online, and they advised bringing two forms of ID to the store. This step may not need further confirmation, but you can check online to avoid a wasted trip.
After work, the store was almost empty. I informed the staff that I needed to replace my SIM card, and they directed me to the counter to proceed with the process.
Provide your IDs and phone number; they will send a verification code via SMS, which you need to provide for verification.
Review the change contract.
The computer screen will display the application for change, showing only the changes from TST to TWM, as shown in the image below. Detailed changes can be found here: Taiwan Mobile - SIM Card Replacement Notice
After completing the process, the staff will confirm and provide the Taiwan Mobile SIM card, advising to switch to the new card the next morning at 6 AM.
About an hour later, I received an official SMS notifying the switch to Taiwan Mobile.
Hello, your mobile number 09XXXXXXXX will be transferred to Taiwan Mobile starting 20240417. Due to system conversion, this number will experience a brief disconnection from 2 AM to 6 AM. Please replace it with the Taiwan Mobile SIM card after 6 AM and back up any data from the old SIM card to avoid loss. For any telecom issues, feel free to contact our smart customer service, Xiao Mai: https://twm5g.co/z8ji
Post-Replacement
In the morning, my phone had no signal, so I switched to the Taiwan Mobile SIM card. The carrier on the top left changed from Taiwan Mobile TS to Taiwan Mobile. After enabling Wi-Fi Calling, I could put the phone in airplane mode to disable LTE, and it would use VoWiFi for calls.
The app login method will update to “Taiwan Mobile Mobile Customer Service” instead of the previous “Taiwan Mobile TS”. After logging in, you can view contract details consistent with the previous Taiwan Star contract. Future telecom-related operations can be completed within the app.
Speed Test Comparison Post-Replacement
Significant improvements were observed at different times at both home and office locations.
| Time | Location | Taiwan Mobile TS (Taiwan Star) | Taiwan Mobile |
|---|---|---|---|
| 6 PM | Location A | 38.3 / 36.9 | 164 / 48.0 |
| 7 PM | Location A | 55.6 / 32.5 | 207 / 52.8 |
| 12 AM | Location A | 93.0 / 42.8 | 192 / 31.0 |
| 2 AM | Location A | 147 / 43.3 | × |
| 8 AM | Location A | × | 236 / 46.1 |
| 12 PM | Location B | 57.6 / 29.7 | 109 / 27.7 |
- Speed is indicated as: download / upload, in Mbps.
- Speed differences are for reference only and consider the following factors:
- Phone’s supported bands
- Bands and bandwidth connected by the phone
- Congestion levels of the bands
- Location and environment
- Temperature
- Taiwan Star and Taiwan Mobile currently use
Multi-Operator Core Network(MOCN) technology to combine networks. The core network is independent, but base station equipment is shared. This allows Taiwan Star users to continue using their original core network while enjoying broader coverage post-merger.
Other Concerns
Will my speed be throttled after replacing the SIM card from Taiwan Star (Taiwan Mobile TS) to Taiwan Mobile?
If throttling were to occur, it could already be done with Taiwan Mobile TS.
Should I replace my SIM card with the 3G network shutting down on June 30, 2024?
The shutdown of the 3G network means that communication must go through 4G or 5G for normal internet access. It has nothing to do with whether you replace your SIM card.
Currently,
Taiwan Mobile TSalready supports VoLTE, so even without switching toTaiwan Mobile, you only need to ensure VoLTE service is activated.Activating VoLTE as per the official process: “Application Path: Log in to the original Taiwan Star APP > Service Application and Settings > Original Taiwan Star VoLTE Service > Agree and apply for VoLTE service.”
For any concerns, it is recommended to call 188 directly or use the online text customer service, which is much more efficient than the original Taiwan Star.
Replacing the SIM card is only necessary if you want the VoWiFi feature. Currently, Taiwan Mobile users can activate it without a monthly fee.
Will 3G really be shut down?
According to the three major telecom operators in the US:
- AT&T officially shut down its 3G network on February 22, 2022.
- T-Mobile’s 3G network was shut down on July 1, 2022.
- Verizon’s 3G network was shut down on December 31, 2022.
Releasing 3G spectrum for 4G or 5G development and use is more beneficial than detrimental. Therefore, it will inevitably be shut down, and most phones will then operate on 4G or 5G signals.
Won’t VoLTE be useless across different carriers?
VoLTE technology allows voice data transmission over LTE, ensuring low-latency calls, less bandwidth usage, and maintaining the LTE connection during calls (without dropping to 3G, 2G, or disconnecting). The feature that might not work across carriers is HD Voice, which affects the call sound quality.
Does VoLTE use data, and how is it billed?
According to Taiwan Mobile, charges are calculated based on domestic rates, meaning in-network and out-network rates follow the existing contract’s monthly fee. It is not free because the call goes through the LTE network.
How is Wi-Fi calling billed when making calls over Wi-Fi?
When making calls from abroad, roaming charges apply. Using VoWiFi avoids these charges, but the call is still billed according to the domestic monthly contract. For example, if a Taiwan Mobile user in the US calls a Taiwan Mobile user in Taiwan, it is billed as a domestic in-network call. If the contract includes free in-network calls, then the call is free.
Does using VoLTE for calls consume my monthly LTE data allowance?
No. VoLTE uses the IP Multimedia Subsystem (IMS) access point name (APN). The IMS APN is specifically for accessing IP multimedia services, such as VoLTE and video communications.
Is
Taiwan Mobile TSconsidered in-network or out-network withTaiwan Mobile?In-network.
Conclusion
If replacing the SIM card is inevitable, why not do it now to benefit from the VoWiFi feature?
However, with the availability of internet connection, services like FaceTime, LINE, Telegram, and Facebook Messenger allow for high-quality, free calls.
Even with VoWiFi, I personally prefer making FaceTime audio calls for high-quality and free voice communication.
The above is for record and reference purposes only.
Appendix (Contract Details. This has been translated from Chinese to English.)
If there are any data changes (such as name change/transfer) or requests for call detail records, please first visit the store for processing before applying for a Taiwan Mobile SIM card replacement. After the replacement, such requests can be processed after the first billing cycle.
After replacing the Taiwan Mobile SIM card, the following billing notice applies:
A. The billing notification method remains unchanged, and call details will be provided according to the bill type (paper copy sent with the bill, e-bill available on the official website).
B. The current bill will be divided into two parts for billing, both of which must be paid. Please pay attention to the payment date, channel, and billing period differences.
C. From the second bill after the change, if the original combined billing is canceled, the billing cycle will be adjusted (delayed by 7-8 days). If adjustments are needed, please apply after the bill is issued.
D. Unused prepayment/excess payment/discount amounts will continue to be deducted according to Taiwan Mobile’s regulations. If there are any remaining amounts upon termination or disconnection, they will be refunded.
If you have any of the following related services, discounts, or benefits, they will be applied according to the following rules after executing the [Taiwan Mobile SIM Card Replacement] operation:
A. If this number still has unused prepayment amounts, they will continue to be deducted according to Taiwan Mobile’s regulations. They can be deducted from the bill in installments, but not for international calls (voice, video, SMS, MMS), international roaming, 0209, donations, third-party payments, compensation/subsidies, mobile device insurance monthly premiums, and other items/fees not deductible according to Taiwan Mobile’s regulations, until the amount is exhausted. However, if there are any remaining prepayment amounts upon termination or disconnection, they will be refunded.
B. If you have applied for an annual rental service for the monthly fee and it has not yet been fully deducted, the deduction will continue, and the original discount benefits will be maintained.
C. MyVideo service (including value-added, contract-bound, and select plans) applied under the original Taiwan Star contract will be deferred to the remaining contract period and discount amount from the Taiwan Mobile SIM card effective date. After the contract expires, the discount will immediately terminate, and the original service monthly fee will apply [Monthly fee is calculated based on the billing cycle. If the service is applied for less than a month, the monthly fee will be calculated proportionally based on the number of days in the cycle].
D. Other value-added or digital services (including KKBOX, number management function, unlimited 66 SMS service, etc.) applied under the original Taiwan Star contract will terminate the subscription from the Taiwan Mobile SIM card effective date. Users can use the original service until the end of the current period. If the original service is contract-bound, it can be used until the end of the current period, and the monthly fee will be settled until the end of the period without any penalty.
E. The original Taiwan Star ringtone service will be transferred to Taiwan Mobile, and the service will continue to be provided by Taiwan Mobile (some songs may change due to supplier factors).
F. The original Taiwan Star Google telecom payment and small payment services will terminate from the Taiwan Mobile SIM card effective date. Users need to re-bind Taiwan Mobile telecom bill payment to use the service. The original Taiwan Star Apple telecom payment can still be used without re-binding. If there are any remaining Taiwan Star credits or unused amounts, please use them before applying for the Taiwan Mobile SIM card. Any remaining amounts will expire from the Taiwan Mobile SIM card effective date.
G. The original Taiwan Star roaming service, if there are any roaming reservations or unused services, should be completed before replacing the Taiwan Mobile SIM card. If you need roaming services, please apply after the SIM card is effective.
H. The original Taiwan Star mobile insurance service, if the original mobile insurance contract has not expired, will be transferred to Taiwan Mobile, and Taiwan Mobile will continue to collect related fees. The original contract period and benefits will remain unchanged.
I. Other service settings and applications, such as VoLTE application, value-added restrictions, international call restrictions, etc., will be processed according to Taiwan Mobile’s current regulations.
J. If you have applied for original Taiwan Star services such as disabling internet usage alerts, restricting certain short codes, disabling data-related services, VoLTE voice call services, etc., they will automatically be enabled according to Taiwan Mobile’s corresponding services from the SIM card effective date. However, if the number is currently suspended or has other conflicting services, the service cannot be enabled.
K. According to Taiwan Mobile’s current 5G service items, the original Taiwan Star 5G video call service will terminate from the Taiwan Mobile SIM card effective date.
If applying for Taiwan Mobile eSIM, the application, activation, and setup procedures and fees are the same as Taiwan Mobile’s current SIM card replacement regulations; please confirm if the device supports eSIM before applying. The actual supported eSIM models are subject to the official announcements of each brand; eSIM setup fee waivers are subject to Taiwan Mobile’s announcements.
Other eSIM-related wearable device services and notices:
A. One Number service application, activation, setup procedures, and fees are subject to Taiwan Mobile’s current announcements; the service requires necessary system environment verification and may conflict with the user’s existing value-added services. Please check the current status of the mobile number before purchasing and pairing. If the mobile number already has applied services, they will automatically be enabled (e.g., rejecting international calls) and linked with the mobile number changes. However, some services requiring APN settings (e.g., content filtering) may not be provided by wearable devices.
B. Apple Watch standalone main and sub-numbers are only applicable to 4G, 5G monthly rental plans. Application requires personal dual ID at all Taiwan Mobile stores. The application, activation, setup procedures, and fees are subject to Taiwan Mobile’s current announcements.