Sales calls, metro commutes, and a phone that is almost never off the network. A salesperson needs to reply on LINE and open a contract a client just sent. A delivery rider needs navigation and new orders. An office worker may join a video meeting from the phone at lunch. The reception problem that actually gets in the way is often not a whole city with no network. It is this: you step into a building or go down to a basement, the phone clearly shows 4G or 5G, and the screen just keeps spinning.
This is not hard to run into in Taiwan. Even with an unlimited plan, the connection can suddenly slow down at one fixed spot. Some people get it back by moving to the window. Others find that a colleague’s phone can send a photo while theirs cannot even send a message.
If the same place keeps doing this, you can report it to your carrier and also give the phone a second way online. Many iPhone, Samsung Galaxy, and Google Pixel models can keep the original number for calls and SMS, and let another eSIM handle mobile data. Before you buy, one point matters: the backup has to be able to use a network other than the carrier that is already weak, or it has little chance of helping.
Why does the phone have a signal when pages still will not open?
The signal bars in the corner show the wireless link between the phone and a base station. They are not a scorecard that says how fast the connection must be right now. The bars can look fine while too many people are online in the same area, the base station is under a heavier load, or the actual data path between the phone and the network is poor. The site can still fail to load.
The building can be the other reason. Elevator lobbies in large office towers, basement floors of department stores, corrugated-metal factories, or meeting rooms with thick walls can weaken a signal once it comes indoors. Video can play smoothly on the street-level arcade downstairs, then drop to 1 or 2 bars beside the desk. On the same floor, the side near a window may work while the other side barely receives anything.
Coverage maps published by Taiwan’s carriers are mostly based on outdoor signal estimates. Official notes from Chunghwa Telecom, Taiwan Mobile, and FarEasTone all mention that terrain, building blockage, the number of users, and the handset can affect connection quality. Seeing “5G coverage near home” is not enough to assume that an underground parking garage, the inside of a factory, or every corner of an office will browse smoothly.
4 common signal situations
| Where it happens | What can go on | What to try first |
|---|---|---|
| Office, commercial building | Partitions, glass curtain walls, thick walls, or many people online indoors at once | Test by a window, and compare coworkers on different carriers |
| Basement, parking | Building shielding, and uneven coverage from indoor signal-extension equipment | Test at an entrance or at ground level; save important information offline first |
| Factory, warehouse | Metal structures, large factory floors, and shielding in certain areas | In areas where phones are allowed, test different carriers on site |
| Metro / commute and field routes | The phone switches base stations while moving, and some stretches and stations differ | Note where it often drops, and download offline maps first |
One stall can be a temporary connection problem. If it happens every day in the same spot, it is more worth comparing how a backup on another carrier behaves there.
What is a dual-SIM backup, and how is it different from buying another data card?
A dual-SIM backup means the phone keeps the original monthly number, and you add a SIM or eSIM that can go online. When you need it, mobile data switches to the spare plan. Say the primary number is Chunghwa Telecom. The commute and home are fine, but one meeting room at a client’s office never loads. If Taiwan Mobile performs better in that spot, an eSIM on the Taiwan Mobile network can be a way to fill the gap.
The reverse is the same idea. If the primary line is Taiwan Mobile, and a warehouse you visit often works better on Chunghwa Telecom in a real test, look at a plan on the Chunghwa Telecom network. If the primary number is FarEasTone, compare the actual reception of the other 2 carriers.
The difference is a different network, not a different brand wrapper. Even if 2 eSIMs come from 2 sellers, they can both lose signal in a corner that carrier does not cover, as long as they end up on the same Taiwanese network. A product that says “dual network” still needs a check of the specific spec: which carriers it supports, and whether it can switch between the 2 networks. The product name alone is not enough.
What dual SIM can help with, and what it cannot fix
A dual-SIM backup fits the case where carrier A is weak here but carrier B can still get online. If the whole building has no usable mobile signal, the company bans phones, or all 3 major carriers are congested in the same spot, a second eSIM will not suddenly produce a base station.
One point is easy to miss: a data-only eSIM will not restore normal mobile voice or SMS on a number that already cannot get a signal. It mainly gives the phone another mobile-data path. If the job requires the original number to be reachable for calls at any time, ask the original carrier about indoor improvements, Wi-Fi calling, call forwarding, and other options that are actually available.
Who should prepare a second Taiwan eSIM?
1. Salespeople who visit clients: files and messages cannot open only at the office
A sales day can mean several buildings. LINE replies go through easily in the ground-floor lobby at one stop. At the next stop, a basement meeting room, the client asks for the quote file and it will not open. More data helps less here than knowing which carrier works better in that building.
If the same large clients come up again and again, note those sites and compare carriers on the spot. A clear difference is a reason to consider a short-day or small-data backup. One occasional small delay does not always justify an extra cost.
Salespeople who need the company VPN, CRM, or a corporate cloud should not test with an ordinary website only. Some travel eSIMs exit through an overseas IP, and a company login region or security policy can limit them. For real work, sign in to your own system and test it first.
2. Delivery riders and logistics drivers: fewer interruptions on navigation and order screens
A delivery route can pass office towers, underground parking, malls, or quiet alleys. If the map suddenly will not update, or the order app freezes, the work pace takes the hit.
Whether a backup helps depends on real coverage along the route, and on what the delivery platform requires of the connection. Test another carrier in the spots that usually stall, then confirm the app can sign in, locate, and update orders. Offline map areas can be downloaded ahead of time, so a weak-signal spot does not also hide the next turn.
On a delivery run or while driving, change network settings only after a safe stop. Do not switch SIMs while riding. The point of a backup is fewer interruptions at work, not one more thing to fiddle with on the road.
3. Factory, warehouse, and industrial-park staff: a fixed dead spot is worth testing early
A metal roof, equipment, and partitions can affect a phone signal, and the same site can be completely different in the admin office, at the freight-elevator entrance, and deep in the warehouse. If the phone is how you report progress, receive photos, or reach company systems, measure the network in each area before deciding whether a backup is needed.
Factories and cleanrooms can have phone rules, and some areas ban personal devices entirely. Work that connects to internal systems, equipment monitoring, or production safety is not a good fit for treating an ordinary consumer travel eSIM as a formal company network. Company IT and on-site communication rules come first.
4. Commuters and mobile office workers: keep the original number, and switch data when you need to
Some people have stable Wi-Fi at home and at the office. The stalls are the daily ride, the station, or a meeting away from the desk. If another carrier happens to be better in those places, dual SIM gives another option.
Frequency still matters. If the weak spot is once a week and only a few minutes, downloading meeting files offline and using Wi-Fi you already have can be more worthwhile than a second line for the long run. Comparing backup cost gets serious when files and cloud systems often have to go up while you are out.
Chunghwa Telecom, Taiwan Mobile, or FarEasTone: how do you pick a backup network?
Taiwan’s 3 major carriers each publish their own coverage and build-out information. None of them keeps the same result in every building and every basement. The same place can also behave differently in the morning and at lunch.
To choose a backup carrier, start with the official coverage pages for Chunghwa Telecom, Taiwan Mobile, and FarEasTone, and check the rough service area of places you go often. Then borrow a coworker or family member’s phone on a different carrier. In the same spot, turn Wi-Fi off, open a page on mobile data, send a LINE image, and test a work app if you need to. Repeat the test a few times at the hours when it usually stalls. That is closer to real use.
Besides download speed, notice how long a page takes to start loading, whether uploads fail easily, and whether the screen often says “no internet.” A speed-test app can log latency and upload speed. A pretty number is not a reason to ignore how the connection feels day to day.
| Current primary number | Backup direction to test first | Check before you buy |
|---|---|---|
| Chunghwa Telecom | Taiwan Mobile or FarEasTone | Whether the JEKO plan you are looking at really uses Taiwan Mobile, and whether a real test works at the workplace |
| Taiwan Mobile | Chunghwa Telecom or FarEasTone | Whether the plan you pick really uses Chunghwa Telecom, and whether the data and validity fit |
| FarEasTone | Chunghwa Telecom or Taiwan Mobile | Which carrier is actually steadier at the regular workplace, then pick a matching plan |
This table is a set of test directions, not a ranking of which of the 3 has the stronger signal. For someone in the same building every day, your spot matters more than the national average download speed.
How do you set up dual SIM on iPhone? Keep the original number for calls, and let the eSIM handle data
iPhone XS, iPhone XR, and many later models can use an eSIM. Models that can keep 2 eSIMs active at the same time vary by model. Before you start, confirm the phone supports it, is not carrier-locked, and install the new eSIM somewhere with stable Wi-Fi or an existing mobile connection.
- Open Settings → Cellular → Add eSIM, and add the plan with the QR Code or install details you received after purchase.
- After it is installed, name the original monthly number “Primary” and the new plan “Backup,” so they are easy to tell apart.
- Open Settings → Cellular → Default Voice Line, and choose the number you normally use for calls.
- Then open Cellular Data and choose the SIM that should go online. If you usually want the primary number, select it first. At a spot with poor reception, switch manually to the backup eSIM.
- If you do not want the phone to switch to another line on its own and use data without you noticing, turn off Allow Cellular Data Switching and switch by hand when you need to. If you still need data during calls, reassess this setting using Apple’s explanation and the actual plan.
- If the JEKO product notes say to turn on Data Roaming, do that only for that eSIM, as instructed. Data Roaming on the primary number does not need to be turned on as well.
Apple’s dual-SIM feature can assign voice and mobile data to different plans, but an iPhone usually uses only 1 mobile-data network at a time. Switching does not add the 2 carriers’ speeds together. The original number can still receive SMS, provided the primary line itself still has working service. When the primary line has no signal at all in a basement, the second data eSIM will not receive traditional SMS on its behalf.
How do you switch on Samsung Galaxy and Google Pixel?
Android menu names change by brand and system version. On a Samsung Galaxy that supports eSIM, you can usually add an eSIM from Settings → Connections → SIM manager, then set the preferred plans for calls and mobile data. Some models show Mobile data or Primary SIM.
On Google Pixel, 2 SIMs are managed from Settings → Network & internet → SIMs, with different plans for calls, text messages, and mobile data. Some newer Pixel models also have automatic data switching, but the conditions still depend on the device version and carrier support.
On any Android phone, 3 things matter most: the new eSIM is added and enabled, mobile data points at the correct plan, and data roaming plus the APN match that card’s install notes. If those menus are not there, check the model and carrier support first. Do not assume every Android phone can do dual-SIM dual standby.
The second eSIM is installed. How do you confirm the backup actually helps?
The simplest test is to take the phone back to the place that drops most often. Turn Wi-Fi off, open the same page on the primary number, send 1 LINE image, and watch the load time. Then switch to the backup eSIM and try the same steps. The comparison is useful when the 2 cards can use different carrier networks.
You can log 3 time windows: just arrived at work, the lunch peak, and afternoon work hours. If the backup eSIM is smoother every time, there is a reason to extend the number of days later. If both are equally slow, the surroundings may be blocking too much, or neither has useful coverage there. Office Wi-Fi, an indoor improvement, or a report to carrier support is the next thing to weigh.
Some people read Automatic network selection as a free switch among Chunghwa Telecom, Taiwan Mobile, and FarEasTone at any moment. The phone can only register on the partner networks the plan is allowed to use. It is not a matter of picking whichever looks strongest. If a product supports dual network, also confirm whether that means automatic roaming switch, manual network selection, or support on specific specs only. Switching usually also means the phone has to register on the network again, and it does not guarantee a handoff with no gap.
When the network suddenly fails, check in this order
Turn Wi-Fi off first, so the test is mobile data. Then see whether the backup eSIM is selected, and whether that card still has validity and high-speed data left. For a roaming eSIM, confirm data roaming and the APN from the order email, then try a brief airplane-mode toggle so the phone searches for a network again. If the screen shows a signal but pages will not open, also look at whether a VPN, private DNS, or company security software is affecting the connection.
There is no need to delete the eSIM at the start. Many QR Code plans do not allow reinstalling as often as you like, and deleting it only makes the search harder. If you need help, keep screenshots of the mobile-data settings, the carrier name, and the error screen, then contact support.
How do you pick a JEKO Taiwan eSIM that can work as a second network?
If you want a short trial first, JEKO Taiwan eSIM plans come in different data forms. Compare them on the JEKO Taiwan eSIM plan overview. When you actually order, choose the carrier, number of days, data allowance, and throttling rules first. Do not look only at the lowest starting price on the same product page.
JEKO Taiwan Daily plans currently use a Taiwan Mobile line. They fit people whose primary number is not Taiwan Mobile and who want to test data quality for a few days. Total and unlimited plans can be chosen from the Chunghwa Telecom or other line specs the product page offers now. If the primary number is already Chunghwa Telecom, buying another eSIM on a Chunghwa Telecom spec usually will not create a real different-carrier backup for the same dead spot.
| JEKO plan type | A way it fits | Check before you choose |
|---|---|---|
| Taiwan Daily | Test 1 to several days at a fixed workplace, or only a small amount of backup data each day | Taiwan Mobile network, the daily high-speed allowance, and the speed after it is used up |
| Taiwan Total | Use is spread out, and you can estimate total data for the whole period | Different specs may use different carriers and different rules when the data runs out |
| Taiwan Unlimited | You need to stay online and do not want to keep counting data use | The specific line, the daily high-speed allowance, the later speed cap, and hotspot conditions |
This kind of JEKO Taiwan data eSIM mainly provides mobile data. It usually does not include another phone number for ordinary calls or traditional SMS. Some plans exit through an overseas network such as Hong Kong or Singapore. They can still connect to base stations in Taiwan, but bank sites, Taiwan-only apps, or a company login can still differ because of IP, verification, and security policy. For a company CRM, VPN, card-payment admin, or work platform, confirm it can fit the way you actually need to use it before you buy.
Validity is the other detail worth noticing. On some plans, the day count starts once the eSIM connects in Taiwan and data traffic is generated. If you are only keeping it for a later day, check the activation rules first. Turning it on too early can use up the valid days.
The useful part of a dual-SIM backup is that you do not have to drop the current monthly plan right away, and you do not have to move a familiar phone number to another carrier. For a short test of a different network, that is the more flexible arrangement. If the second card has to carry long hours every day, compare the long-term cost with an improvement from the original carrier or with a formal switch.
Taiwan dual-SIM backup FAQ
If the phone shows full bars but no internet, is it definitely a carrier signal problem?
Not necessarily. Besides a congested base station, the Wi-Fi itself may be down, mobile data may be on the wrong line, the allowance may be used up, or a VPN or app may be the problem. Turn Wi-Fi off and try another page, and the cause gets narrower step by step.
Can a second eSIM make a Chunghwa Telecom primary line connect through Taiwan Mobile instead?
It does not change the carrier that owns the original number. Dual SIM adds a separate data plan, and you choose that eSIM for data when you need it. Voice and SMS on the Chunghwa Telecom number still come from Chunghwa Telecom.
Will the existing LINE account, banking apps, or phone number change?
Usually not. A data eSIM only gives the phone another network. It does not move the LINE account or the Taiwan phone number away. Some finance and company apps do check the login environment and IP location, so test before real use.
Can the 2 cards add their 5G speeds together at the same time?
Ordinary phone dual-SIM settings do not merge the speeds of 2 SIMs. On iPhone, 1 mobile-data network is used at a time. The value of a backup is having another line you can choose.
If it says dual network, can you switch to any of the 3 major carriers whenever you want?
No. Dual network usually means the 2 networks the product is allowed to use. It does not mean every carrier in Taiwan is open, and the switching method also depends on the plan. Look at the specific spec you selected.
After you switch to an eSIM, can you still receive the original verification codes?
As long as the primary number stays active, has a normal signal there, and can receive SMS, you can keep receiving OTP on that number. If the primary line has no signal at all in a basement, the data eSIM itself will not receive traditional SMS for it.
If the network is poor, does turning 5G off and using 4G help?
In some environments it can be a test option, and it does not always work. Base stations and phones can behave differently on 4G and 5G. If a fixed spot stays poor for a long time, compare real coverage and report it to the carrier.
Can delivery or work apps use a JEKO backup directly?
Ordinary pages and messages often work. Important work apps may have limits on IP, VPN, location, or security. Finish a login and order-flow test outside peak work hours before you decide to depend on it for the job.
The eSIM still shows a signal after the data runs out. Why is there no internet?
Different products follow different rules. Some reduce the speed. Some stop providing data. A carrier signal on the phone does not mean the plan still has enough usable data. Check the high-speed allowance, the validity, and the fair use policy of the plan you selected.
A backup is useful when it works in the places you actually go
Before buying a second eSIM, the step that is worth more is not researching which carrier is the fastest across all of Taiwan. Look back at where you need a network every day. Client visits mean testing meeting rooms and office buildings. Delivery means testing the stretches that stall. People who work in a factory site should watch the work areas where phones are allowed.
If another carrier really is smoother in those places, a short-term eSIM has a chance to be a useful backup. If both are poor, telling the carrier and looking for an indoor network improvement usually helps more.
To see which line and data combinations are available now, choose on the JEKO Taiwan eSIM plans page. Leave the original number as it is, add one more way to connect at the work spots that keep stalling, and the workday and the commute can feel a bit more manageable.
