When you buy a travel eSIM, you often see the promise of "4G/5G at maximum speed," but then you load Instagram, and it doesn't fly like it does at home. The actual speed of an eSIM almost never matches the advertised speed, and it's not a scam: it's how mobile networks work. Here, I'll explain what to really expect, what limits your connection, and how to measure and improve it.
Why isn't the actual speed the one advertised?
The advertised speed is a theoretical maximum of the technology (what the network provides under ideal conditions), not what you'll see on your screen. The actual speed depends on the local operator's network your eSIM connects to, congestion, your location, and even your phone. It's normal to receive a fraction of the advertised maximum, just like with your home internet connection.
Put simply: an eSIM gives you the same speed a local would get with that operator in that location at that time. There's no special "eSIM speed"; you're using the country's infrastructure. That's why you'll go super fast in Tokyo and not so fast in a mountain village.
Think of it like a car's advertised fuel consumption: the manufacturer gives a figure measured in the lab, and then your actual consumption depends on how and where you drive. The same goes for your connection. The advertised speed is the display; what you see on your phone is the result of your specific situation. Understanding this saves you frustration and helps you choose a plan wisely, without falling for "unlimited speed" promises that no network can guarantee everywhere.
What 4G and 5G really mean
In practice, good 4G/LTE gives you between 10 and 50 Mbps download speed, more than enough for almost everything a traveler does: maps, HD streaming, video calls, and social media. 5G can reach hundreds of Mbps where it's deployed, but for viewing a map or sending photos, you won't notice the difference compared to decent 4G.
| Technology | Typical actual speed | Sufficient for |
|---|---|---|
| 3G | 1-5 Mbps | Messaging, maps, light websites |
| 4G / LTE | 10-50 Mbps | HD streaming, video calls, all normal activities |
| 5G | 100-500+ Mbps | Large downloads, intensive hotspot use |
If you want to delve deeper into the generation leap, you can find more details on 5G speed in eSIMs.
Factors that slow down your eSIM
Before blaming the eSIM, check what's really limiting the connection. It's almost always a combination of these factors:
- Site coverage: inside a building, in a valley, or on the subway, the signal drops even if the plan is for maximum speed.
- Network congestion: at a festival, a crowded airport, or downtown at midday, thousands of phones compete for the same antenna.
- Your phone: an old device might not capture the country's 4G/5G bands.
- Data policies: some plans reduce speed after consuming a certain daily amount; it's advisable to read the fine print.
Key fact: if your plan says "unlimited data," there's almost always a period of maximum speed, and then it's reduced. This isn't a trap exclusive to eSIMs; physical plans do it too.
To avoid surprises, check if unlimited data really exists for eSIMs and what it implies in practice.
How to measure your actual speed
Measuring is easy and removes doubts in 30 seconds. Use a reliable speed test (like Speedtest) and follow these rules for a fair test:
- Do it outdoors, with a good signal, not inside the hotel.
- Check that your phone shows 4G or 5G, not 3G or "E".
- Repeat at different times: the network doesn't perform the same at 3 PM as it does at midnight.
- Note the latency (ping) in addition to the download speed: for video calls, it's as important as Mbps.
If the test results are good but an app is slow, the problem is usually with that app or its server, not your eSIM.
Speed needed per task
The good news: for travel, you need much less speed than you think. An average traveler has more than enough with normal 4G:
- WhatsApp and maps: 1-3 Mbps is plenty.
- Social media and browsing: 5-10 Mbps is fluid.
- HD streaming and video calls: 5-15 Mbps is sufficient.
- Hotspot for laptop: the more, the better, but 20 Mbps already provides an office-like experience.
In other words, even if you don't reach the advertised maximum, you'll almost certainly have more than enough speed for what you do during your trip. If you're going to work, review how to share your connection via hotspot without dying in the attempt.
A note on latency: Mbps measures how much data passes, but ping measures how long it takes for each packet to travel back and forth. For browsing or watching videos, it barely matters, but in video calls or video games, high ping is more noticeable than a few less Mbps. If your call breaks up with good download speed, the culprit is almost always that network's latency at that moment, not the eSIM.
How to get more speed
If you notice it's slow, try these adjustments before giving up:
- Restart the connection: activate and deactivate airplane mode so the eSIM re-engages the best antenna.
- Force 4G/5G in network settings if your phone is stuck on 3G.
- Move a few meters or go outside: sometimes a wall changes everything.
- Manually select the network if your eSIM allows it, to escape a congested operator.
And if you suspect the problem is with the settings, this list of common eSIM problems will help you diagnose it. To squeeze every megabyte, don't forget the tricks to save data abroad.
Frequently asked questions
Is an eSIM slower than a physical SIM?
No. Both eSIMs and physical SIMs use the exact same local operator network, so the speed is identical under equal conditions. The difference lies in the convenience of activation, not in connection performance.
Why is my eSIM slow if I have 5G?
Having the 5G icon doesn't guarantee maximum speed: there might be congestion, poor actual coverage of that band, or plan limits. Try running a speed test outdoors and at different times to see what you actually get.
How do I know my actual speed?
With a speed test app like Speedtest, outdoors and with good signal. Look at the download speed (Mbps) and the ping. Repeat the test at various times, because the network changes a lot depending on the time of day and the number of people connected around you.
Is the advertised speed a lie?
No, it's a theoretical maximum of the technology under ideal conditions, not a promise of what you'll see. It works the same way as your home fiber: you contract a speed "up to X" and in practice, you get something less depending on many factors.
How many Mbps do I need for travel?
Very few: with 5-10 Mbps, you can browse, use maps, watch HD videos, and make video calls without problems. That's why, even if you don't reach the advertised maximum, you'll almost always have more than enough speed for everything you do during your trip.
Conclusion
The actual speed of an eSIM depends on the country's network, coverage, and congestion, not on a provider trick: that's why you'll rarely see the advertised maximum, and you don't need it either. Measure with a test, adjust the network, and choose an honest plan. With a quality eSIM, you'll have more than enough speed to travel connected without surprises.
