You are in Kyoto. Three days left on your trip. Your Japan eSIM shows 127 MB remaining. Tomorrow you have a full day in Nara and the day after in Osaka. You need navigation for both days. Here is exactly what to do.
Three Options When Your eSIM Runs Out
| Option | How fast | Best for | Notes |
|---|---|---|---|
| Top up existing plan (same provider) | Instant if provider supports it | Most convenient — same eSIM line | Not all providers offer top-ups |
| Buy new eSIM plan (new QR code) | 5–10 minutes on WiFi | Any provider supports this | Need hotel WiFi to install new QR |
| Use hotel WiFi and offline Maps | Immediate | Short remainder of trip with light needs | No mobile data for navigation between hotels |
| Airport or local SIM as backup | 15–45 minutes at a counter | Last resort if no WiFi available | Most expensive option |
How to Top Up or Buy a New Plan
Step 1 — Connect to any available WiFi: Hotel WiFi, cafe WiFi, or a friend's hotspot. You need internet to purchase a new plan or access top-up functions.
Step 2 — Check if your provider offers top-ups: Open your provider's app or website. Look for top-up, add data, or refill. Some providers allow you to add data to your existing eSIM profile without scanning a new QR code — the additional data simply extends your existing line.
Step 3 — If no top-up available, purchase a new plan: Buy from any provider. You will receive a new QR code by email. Install it via Settings, Cellular, Add eSIM, scan QR. This creates a second eSIM profile on your phone. You can have both profiles installed — just set the new one as your mobile data line.
Step 4 — Stretch remaining data with offline Maps: If you have 100–200 MB remaining: download offline Google Maps for your remaining destinations immediately. 200 MB covers offline maps for a city-sized area. Navigation then works without consuming more data. Use remaining data only for messaging and essential app functions.
What Consumes the Most Data Without You Realising
Three common data drains travelers discover too late: Google Photos automatic backup on mobile data (turn off in Photos settings — set to WiFi only). App background refresh on multiple apps simultaneously while your phone is in your pocket. Social media auto-play video in feeds while scrolling. Check your data usage breakdown in Settings, Cellular — it shows which app has consumed the most data. Turn off background app refresh for the heaviest consumers if stretching remaining data.
The China-Specific Problem: Running Out Inside China
Running out of data inside China is more complicated because: eSIM provider websites may be blocked by the firewall, making it difficult to purchase a new plan on Chinese WiFi. New QR code activation may fail because the provisioning servers are blocked inside China.
The solution if you anticipate running low in China: purchase a new China eSIM plan before your data runs out while your existing connection still works. Use your remaining China eSIM data to access your provider's website and purchase the top-up or new plan. Download the QR code while you still have working mobile data. Install the new profile on hotel WiFi. This proactive approach avoids the scenario of being out of data and unable to reach your provider's servers from inside China.
Conserving Data for the Last Few Days
If you have 300–500 MB remaining and 3 days left: the priority order for data conservation is navigation (Google Maps) first, messaging (WhatsApp text) second, everything else on WiFi only. Steps to take: turn off mobile data for Instagram, TikTok, Twitter, and any video app. Switch Google Photos to WiFi only. Turn off Cellular Data for all apps except Maps and WhatsApp in Settings, Cellular. Enable Low Data Mode on iPhone (Settings, Cellular, eSIM line, Low Data Mode) — this reduces background data consumption across the system.
FAQ
Can I install a second eSIM while my first one is running low?
Yes. Modern phones support multiple eSIM profiles simultaneously. Purchase a new plan, install the new QR code on hotel WiFi, set the new profile as your mobile data line in Settings. Your old eSIM profile remains installed but inactive. You now have full data again on the new profile. Some phones limit simultaneous active lines to two but can store more profiles.
My eSIM ran out of data in Japan — can I buy more without hotel WiFi?
If you have any signal remaining but data is exhausted: switch your home SIM to mobile data temporarily (it will use your carrier's roaming rates), connect to your provider's website, purchase a top-up or new plan, download the new QR code, then switch your home SIM data off again. This uses a small amount of home carrier roaming data — the cost is minimal for a short transaction — to restore your travel eSIM. An alternative: any cafe or convenience store with WiFi works for the QR code installation.
What if I want to avoid this situation on future trips?
Choose a plan one size larger than your estimate. The difference between a 5GB and 10GB plan is typically $4–6 and eliminates the mid-trip data anxiety entirely. A 10GB plan covers most 14-day trips even with heavy navigation and daily social media without coming close to the limit. The cost of the extra plan headroom is less than the cost and friction of one top-up transaction.
Running low? Buy your top-up now while you still have data: Japan eSIM · Europe eSIM · China eSIM · Global eSIM