In short: in the Holafly vs Saily comparison, there is no objectively better eSIM: Holafly sells unlimited data for a flat rate, designed for not watching the meter; Saily sells cheaper closed GB packages, designed for those who control their consumption. Choose based on how many days you travel and how many GB you actually use per day, not on the brand.
Holafly vs Saily in 30 seconds
Holafly built its brand around a single argument: unlimited data for days, with no meter to watch. Saily, which originated from the people behind NordVPN, opted for the opposite model: closed GB packages and lower entry prices. Neither philosophy is inherently superior. It depends on how you travel, not which one has better marketing.
The difference is most noticeable at two points: when you buy (do you pay a flat rate or choose a package?) and when you run out of data (does it never run out, or do you have to top up?). Before deciding, it's worth understanding what data roaming is and why both eSIMs exist precisely to avoid it.
Quick rule: if you're going to use maps, social media, and streaming without thinking twice, unlimited data will pay off. If you use your phone wisely—maps, messaging, some scrolling—a per-GB plan is almost always cheaper.
Data model: unlimited vs. per GB
This is the core of everything. Holafly sells connection days with no volume limit: you buy 7, 15, or 30 days and browse without watching how much you've spent. The fine print that almost no one reads is that this "unlimited" usually comes with a speed reduction (throttling) after a certain daily consumption in some destinations. You don't lose connection, but it can be significantly slower after a certain point, especially during peak hours.
Saily works the other way around: you choose a GB package with a specific validity period and browse at full speed until you run out. If you have data left over, you lose it when it expires; if you run out, you top up from the app instantly. For a one or two-week city trip, a small package is usually more than enough if you monitor streaming video, which consumes by far the most data.
What does "reduced speed" mean in practice?
It doesn't mean the internet stops working. It means that, after a certain daily threshold, your connection may switch from 4G/5G to a more limited speed, sufficient for WhatsApp and maps but uncomfortable for watching high-quality video. If your priority is guaranteed speed from start to finish—for example, for work video calls—it's advisable to compare the actual vs. advertised speed before deciding on an unlimited plan.
- Unlimited (Holafly): zero mental management, flat rate, but with possible speed reduction after certain consumption.
- Per GB (Saily): lower entry price and full speed while the package lasts, but requires careful consumption estimation.
Real price: when each model pays off
The "per day" price on the website is more misleading than it seems. An unlimited plan looks expensive on paper compared to a small GB package, but if you're going to consume a lot—video, data calls, remote work—it still pays off. A per-GB plan seems like a steal, but if you miscalculate and top up twice mid-trip, you could end up paying the same or more than the unlimited plan you initially dismissed.
The right way to compare is not to look at the headline price, but to cross-reference two pieces of information: how many days you'll be away and how many GB you genuinely use on a normal travel day (not a day of downloading entire series). If you've never measured it, check your mobile data consumption at home during a typical week: that number, not the one you'd like to spend, is your real starting point.
| Travel Profile | Usually Pays Off | Why |
|---|---|---|
| 3-4 day getaway, light use | Saily (per GB) | A small package covers maps and messaging without overpaying |
| Week or more with streaming and work | Holafly (unlimited) | No data rationing or mid-trip top-ups needed |
| Long trip, medium or irregular consumption | Depends on calculation | Result changes based on actual GB used per day |
| Remote work with video calls | Per GB with full speed | Prioritizes guaranteed speed over unlimited volume |
As a general market reference: data eSIMs are almost always much more economical than activating your Spanish operator's traditional roaming outside the European Union, where the cost per megabyte skyrockets without prior notice if you don't contract anything before leaving. Don't trust specific figures you see around: prices change frequently, so always check the current price on each provider's website before buying. To understand why this happens, take a look at our comparison eSIM vs. roaming.
Coverage, real speed, and data sharing
Both eSIMs rely on local networks of real operators, not their own infrastructure, so coverage in cities and tourist areas is usually solid for both. The significant differences appear in the details: how many countries each plan covers, whether they allow data sharing via hotspot, and how speed behaves when the local network is saturated, which is common in very touristy areas at midday.
Tethering (sharing data with your laptop) is a point that is often forgotten and then causes frustration at the destination. With per-GB plans like Saily's, sharing data simply uses up your contracted allowance, with no additional restrictions. With unlimited plans, some operators limit or penalize hotspot use to prevent it from being used as a fixed home Wi-Fi line. If you're going to work with your laptop and need your phone as a router, check this condition in the plan details before paying; if your plan restricts it, you might want to consider a pocket Wi-Fi router as an alternative or complement.
Tip: If you need guaranteed speed for a specific meeting—not in the background, but at the exact moment of the video call—a per-GB plan with full speed is usually more reliable than an unlimited plan that might be slowed down depending on the time.
App, activation, and support
Both are installed by scanning a QR code or directly from their app, without visiting a store or touching the physical SIM card. Activation takes just a minute: you buy, install the eSIM profile, and decide when the plan starts counting. There's a nuance here that's often overlooked: install the profile calmly, at home and with Wi-Fi, but don't activate it until you land or need it, because with many plans, the day counter starts at the moment of activation, not at the time of purchase. If you have questions about the step-by-step process, we explain it in how to install an eSIM.
The real difference in experience lies in the app: how clear the remaining consumption warning is, how easy it is to top up without leaving the application, and whether it notifies you before you run out of data or leaves you to discover the cutoff yourself, usually at the worst possible moment. For support, both offer chat assistance; for a Spanish traveler, having support that responds in Spanish at odd hours—in the early morning due to the destination's time zone—makes a real difference when something doesn't connect and you don't have backup Wi-Fi.
What almost no one tells you
Beyond the comparative features, there are small details that are only discovered by using these eSIMs several times:
- "Unlimited" does not always mean the same thing in all destinations. The threshold at which speed is reduced varies by country; in some destinations it is generous, in others it is noticeable sooner. If your trip is to a single country, it's worth checking the specific conditions for that destination before assuming that unlimited behaves the same everywhere.
- Buying the largest GB package "just in case" doesn't always save money. With Saily, unused data expires with the plan. If you're debating between two sizes, it's better to run short and top up on the fly—it takes seconds in the app—than to overpay for margin you'll never use.
- The mobile phone must be eSIM compatible and unlocked. This is not exclusive to Holafly or Saily, but it is the most common reason why someone cannot install an eSIM the day before traveling. Check this in advance, not at the check-in queue.
- Older iPhones and Androids with active dual eSIMs can experience battery or network issues if you keep both data lines active simultaneously. The usual practice is to leave the Spanish line only for calls/SMS and the travel eSIM as the data line, deactivating your operator's data roaming so it doesn't compete for the network.
- At land borders or on cruises that pass through several countries, check if the plan you purchased covers all countries on the route or only the final destination: this is a common source of surprises when the ship or bus crosses from one country to another and coverage disappears without warning.
Which eSIM to choose based on your type of trip
With all the above, the choice can be simplified by traveler profile:
Weekend city break
For a two or three-day getaway to a European city, you don't need unlimited data: a small GB package covers maps, messaging, and social media sufficiently. Here, Saily usually comes out ahead. And if the destination is within the European Union, before buying anything, check if your Spanish tariff already includes free roaming in that country: for a weekend in the EU, often no additional eSIM is needed.
Long trip or multi-country travel
If your route crosses several countries on the same trip, compare whether a regional eSIM that automatically switches coverage or a per-country eSIM that you have to replace is more convenient. This decision is as important as the Holafly vs Saily choice, so we dedicate a separate comparison to it: regional eSIM vs. per-country eSIM.
Remote work or digital nomad
If you rely on your phone as a router for work, prioritize full speed and unrestricted hotspot capability over unlimited volume. Here, it's also worth considering whether a local physical SIM makes more sense for multi-week stays in the same country, where the cost per GB usually drops significantly compared to any international eSIM.
Family or group with multiple phones
Each person needs their own eSIM (you can't share one among several phones), so the savings multiply by the number of devices. Here, a tailored GB package is usually cheaper than paying for several unlimited plans, unless someone in the group is going to use a lot of data.
If your next destination is Europe, you can directly view our eSIM for Europe and compare prices and GB against what Holafly and Saily offer for the same destination.
Frequently asked questions
Is Holafly better than Saily?
Not absolutely. Holafly wins if you want unlimited data and don't want to ration it on long trips or heavy usage. Saily wins on price if you control your spending and a closed GB package is enough for you. It depends on your travel profile, not on which brand sounds better.
Is Holafly's unlimited plan really unlimited?
It offers unlimited data volume, but in some destinations, speed is reduced after a certain daily consumption. You won't lose connection, but it might be slower during peak hours or after very intensive use. It's advisable to check the specific conditions for the destination before assuming it behaves the same in all countries.
Which is cheaper, Holafly or Saily?
As a general rule, Saily's per-GB packages have a lower entry price than Holafly's unlimited plans. The exception is the traveler who consumes a lot of data daily: in that case, an unlimited plan might pay off compared to topping up a small package multiple times. Always check the current price on each website, as it changes over time and by destination.
Can I share data (hotspot) with both?
With per-GB plans, tethering usually just consumes from your contracted allowance, with no added restrictions. With unlimited plans, some operators limit or penalize hotspot usage. If you're going to use your phone as a router for your laptop, check this condition in the plan details before purchasing.
When should I NOT buy either of them?
If you're traveling within the European Union with a Spanish tariff that includes roaming, you probably already have free coverage at your destination, and buying an additional eSIM would be an unnecessary expense. Check with your operator before paying for anything.
Can I install the eSIM before traveling and activate it upon arrival?
Yes, and it's recommended. Install the profile calmly, at home and with Wi-Fi, but don't activate it until you need it: with many plans, the day counter starts running from activation, not from purchase or profile installation.
Do I need to lose my WhatsApp number if I use a data eSIM?
No. The eSIM only provides data connection; your number and WhatsApp remain linked to your Spanish SIM. You keep your home line active for calls and SMS, and use the eSIM solely for browsing without paying data roaming fees.
Conclusion
Holafly and Saily solve the same problem—connecting outside of Spain without roaming—with two opposing philosophies: the peace of mind of a flat rate versus savings from measured GB. Calculate your travel days and your actual daily consumption, not what you'd like it to be, and the choice becomes much more obvious than it initially seems. And before deciding on either, always compare with at least one other provider: the winning eSIM isn't the one with the strongest marketing, but the one that best fits how you travel.
