Frequently Asked Questions

An eSIM, or embedded-SIM, is a digital SIM card built directly into your device that functions without the need for a physical SIM card. It allows users to download and activate cellular services over the internet, providing a more convenient and flexible experience. This eliminates the need for physical card swaps, making it especially beneficial for international roaming.

Using the Mars eSIM Physical Card instantly upgrades your non-compatible phone with eSIM functionality, so you never have to worry about internet issues while traveling abroad.

The card looks exactly like a standard physical SIM card. Simply insert it into your phone's SIM slot, and your device will gain an extra eSIM space where you can download and manage data plans from various countries at any time.

Please verify your device's compatibility before purchasing. You can check using the following methods:
1. Dial *#06#: Open your phone's dialer and enter *#06#. If an EID number is displayed, your device likely supports eSIM. Please note: This method is for preliminary assessment and does not guarantee 100% compatibility.

2. Check Settings: Before placing an order, go to your phone's settings and look for options such as "Add eSIM," "Add Data Plan," or "Add Cellular Plan." If these options are visible, your device is eSIM-ready.

3. Please ensure that your device is "unlocked." An unlocked phone allows you to use eSIM cards from different carriers. In some cases, even if a phone model supports eSIM, certain countries or regions may impose restrictions that prevent eSIM usage or limit it to specific carriers only.

⚠️ Reminder: Issues such as regional version differences, carrier locks, or incompatible older models must be verified and resolved by the user prior to purchase.

Many phones (especially contract-based devices from abroad) are tied to a specific carrier, known as a "Carrier Lock." If you are unsure if your phone is unlocked, please follow these steps to check:

For iPhone Users

1. Go to Settings > General.
2. Tap About.
3. Scroll down to the "Carrier Lock" section:"No SIM restrictions": Congratulations! Your iPhone is unlocked and ready for Mars eSIM."SIM locked": This means your device is restricted. Please contact your original carrier to request an unlock.

For Android Users

1. Go to Settings > Connections (or "Network & Internet").
2. Select Mobile Networks > tap Network Operators.
3. Turn off "Select automatically" to scan for available networks:Multiple carrier names appear: Your Android phone is unlocked.Only your current carrier appears: Your phone may still be locked.

💡  Pro Tip:
If you confirm your phone supports eSIM but it appears locked, contact your original carrier and mention you need to use the device abroad to make a request.

For iPhone Users: Before activating your eSIM, go to Settings > Cellular. Scroll to the bottom and tap "Reset Statistics." You can then monitor your usage under "Current Period" in the "Cellular Data" section.

For Android Users: You can typically view your daily or total data usage under the "Network & Internet" or "Data Usage" section within your phone's Settings.

When your speed is limited to 128kbps, you can still send and receive text-based emails and messages (such as text on LINE or WhatsApp). However, browsing websites or using social media will be significantly slower, and loading content will require more time.

Network speeds may vary depending on factors such as the density of local base stations, location, terrain, building interference, number of concurrent users, and weather conditions.

⚠️ Important: Please note that telecommunications infrastructure varies by country. Dissatisfaction with network speed due to local infrastructure does not constitute grounds for a refund. ⚠️

The Fair Usage Policy (FUP) is a set of guidelines implemented by local telecommunications carriers to maintain network quality for all users. When an individual consumes an excessive amount of data in a short period—through activities such as streaming high-definition videos, live broadcasting, video calling, or downloading large files—the carrier may temporarily reduce (throttle) their connection speed. This ensures that a single high-bandwidth user does not negatively impact the internet experience of others, allowing everyone to enjoy reasonable connection quality.

Most eSIM plans available on the Mars eSIM Store support 5G connectivity, though some regions are limited to 4G services. Please note that actual internet speeds may vary based on factors such as local carrier coverage, location, terrain, building interference, number of concurrent users, and weather conditions.

Currently, the eSIM plans available on the Mars eSIM Store are data-only and do not include a local phone number. If you need to make calls or send messages, we recommend using communication apps such as LINE, WhatsApp, or Messenger.

Yes, all eSIM plans available on the Mars eSIM Store support hotspot sharing. As long as your device has a personal hotspot feature and the eSIM itself supports sharing, you can connect other devices through your eSIM.

⚠️ Note: Hotspot sharing can consume data very quickly. To ensure the best experience and prevent early data exhaustion, we recommend purchasing a dedicated eSIM for each device. ⚠️

Yes, installing an eSIM only changes your network source; it will not delete or affect the data and settings within your apps.

⚠️ Important Notice: Due to varying telecommunications policies in different countries, we cannot guarantee that all apps will function normally across borders. Please be aware of potential local restrictions. ⚠️

Before Activating Your eSIM Abroad — Have You Set Up Your Taiwan Number?
Even if you’re using an eSIM for internet access while traveling, you’ll still need to keep your Taiwan mobile number active to receive verification codes (such as for LINE, banks, or social media logins).
Please make sure to complete the 3 steps below before you travel:

✅  Step 1: Enable Voice & SMS Roaming on Your Taiwan SIM
Before you leave Taiwan, contact your mobile carrier to ensure the following features are enabled: 

• VoLTE raoming
• International calls
• International SMS

🔔 Note: Many Taiwanese users have international features disabled by default — make sure to check in advance!

✅  Step 2: Set Your Taiwan Number as the Default for Calls/SMS
If you’re using a Taiwan SIM for SMS and a foreign eSIM for data, you must set your Taiwan number as the default for voice/SMS.
Otherwise, you won’t receive verification messages abroad.

📱 How to set it up on different phones:
◉ iPhone
Settings > Cellular > Default Voice Line > Select your Taiwan number (+886)
◉ Google Pixel
Settings > Network & Internet > SIMs > SMS Preference > Choose Taiwan number
◉ Samsung Galaxy
 Settings > Connections > SIM Manager > Text Messages > Choose Taiwan number

✅ Step 3: Receive Taiwan SMS While Abroad
 Once the settings above are complete, you’ll be able to:

•  Receive Taiwan SMS abroad normally (e.g. OTP, LINE verification, banking messages)
• Sending SMS may incur roaming fees — please check with your carrier

💡 Tip: Receiving SMS is usually free, but sending may cost extra.