Galaxy S25 eSIM Not Working in Vietnam: Causes and Fixes

The Galaxy S25 eSIM not working issue is becoming a common concern for travelers who bring their new Samsung flagship to Vietnam. While eSIM is designed to make connectivity seamless, many users have reported activation failures, data connection drops, or inability to detect the local eSIM profile. This article provides a comprehensive troubleshooting guide, based on real user cases, carrier guidelines, and device-specific settings. It also links back to the full eSIM setup guide for Vietnam.

📌 Why eSIM Problems Occur on Galaxy S25 in Vietnam

Even though the Galaxy S25 officially supports eSIM globally, there are multiple factors that can cause problems when traveling:

• Carrier Lock: If your device is locked to AT&T, Verizon, or another provider, Vietnamese eSIMs (Viettel, MobiFone, VinaPhone) will not activate.
• Firmware Issues: Early Galaxy S25 firmware releases had bugs related to dual SIM/eSIM handling, requiring security patch updates.
• APN Configuration: Incorrect APN values prevent internet access, even after eSIM installs successfully.
• Region Mismatch: Some users buying S25 Ultra in the US noticed eSIM disabled by default; only EU/Asia variants support multiple eSIM profiles.

🛠️ Step-by-Step Fix for Galaxy S25 eSIM in Vietnam

1. Check eSIM Status: Go to Settings → Connections → SIM manager. Ensure “Add eSIM” is available.
2. Scan QR Code Again: Some profiles fail on first try. Use SIM manager → Add mobile plan → Scan QR.
3. Update Software: Navigate to Settings → Software update → Download and install. Ensure you’re on the latest security patch (as of August 2025, Android 15 build fixed eSIM bugs).
4. Manually Configure APN:
   • Viettel: v-internet
   • MobiFone: m-wap
   • Vinaphone: m3-world
5. Force 4G/5G Mode: Go to Settings → Mobile networks → Preferred network and select 4G/5G only.
6. Disable Conflicting SIM: If using dual SIM, temporarily disable the foreign physical SIM to avoid conflicts.
7. Restart Device: Many eSIM profiles activate only after rebooting.

📊 Real Case Studies from Travelers

In June 2025, a German traveler reported that his Galaxy S25 Ultra purchased in Berlin failed to recognize Viettel eSIM. After applying the July 2025 patch, the eSIM installed normally.

Another case in July 2025: a Singaporean business traveler installed a MobiFone 30-day plan (6GB/day). The eSIM activated instantly, but data did not work until he manually updated the APN. Once fixed, speeds reached 170 Mbps in Ho Chi Minh City on 5G.

According to Ookla’s Speedtest Global Index, Vietnam’s average 5G speed in Q2 2025 was 210 Mbps. This confirms that when properly set up, Galaxy S25 can achieve global-class connectivity.

⚡ Common Error Messages and Solutions

• “Unable to activate eSIM”: Device may be carrier-locked. Contact your original provider.
• “No service” after activation: Check APN and preferred network mode.
• “Mobile plan already in use”: Contact provider for a fresh QR code (some QR codes expire after 3 attempts).

📱 Best Practices for Smooth Setup

• Purchase eSIM before departure to avoid airport Wi-Fi issues.
• Keep a screenshot of QR code in case email fails offline.
• Ensure at least 20% battery when installing eSIM (interruption may corrupt profile).
• Run a speed test after installation to confirm stable connection.

🌐 Which eSIM Plans Work Best on Galaxy S25?

Based on customer usage in 2025, here are recommended options:

• Viettel eSIM (5GB/day, $13.50–$18.50): Best for strong 4G/5G coverage in rural areas like Ha Giang, Sapa.
• MobiFone eSIM 30 days (6GB/day + free calls, $18.50): Suitable for travelers needing a local VN phone number.
• MobiFone eSIM 20 days (4GB/day, $14.50): Balanced data + validity option.

For more detailed setup guides, see the eSIM Setup in Vietnam (iPhone, Samsung, Pixel, more).

You may also check Samsung’s official support on Galaxy S25 connectivity.

✅ Final Checklist Before You Travel

• Confirm your device is unlocked.
• Download the latest Galaxy S25 firmware update.
• Purchase your Vietnam eSIM online before departure.
• Save your QR code securely (offline access).
• Know your carrier’s APN settings.

📞 Need Help?

If your Galaxy S25 eSIM is not working in Vietnam even after these fixes, contact our support team for troubleshooting and replacement options.

Contact: WhatsApp: +84 98 307 49 15 | LINE ID: anyaxiaoying | Email: info@govnsim.com