I'm going to start where almost no one does: if you have a normal Spanish mobile plan, internet in Greece is probably already included. Greece is part of the European Union, and that changes the whole conversation. Even so, every summer I see travelers burn through their data plan in three days in Mykonos or get hit with a bill for hundreds of euros on a ferry. Here, I compare all the real options—European roaming, hotel Wi-Fi, local Greek SIM, and eSIM—and tell you honestly when each one is worth it.
The four ways to get connected in Greece
To get internet in Greece, you have four options: use your Spanish plan with European roaming (included at no extra cost), rely on hotel and cafe Wi-Fi, buy a prepaid Greek SIM from Cosmote, Vodafone, or Nova, or activate a data eSIM. The best option depends on your plan and your itinerary.
That's the short answer. The long answer is that these four options don't compete on equal terms: each one wins in a specific scenario and dramatically loses in another. European roaming is unbeatable if your plan has plenty of data. Wi-Fi is free, but it ties you to a location. A local SIM offers the best price per gigabyte if you stay for weeks, at the cost of losing your number. And an eSIM fills the gap left by the other three: abundant data, no paperwork, and no need to find a store open on a Sunday in Naxos.
My criterion, after setting up dozens of data configurations for trips across Europe, is simple: first check what you already have, then how much you'll consume, and only then decide if you need to buy anything. If you prefer to get straight to the point with the digital option, I have a specific guide for eSIM for Greece with activation steps.
Roaming with your Spanish plan: what’s really included
Here I need to be honest, even though I sell eSIMs. Due to the European regulation "Roam Like At Home", your Spanish operator is obliged to let you use calls, SMS, and data in Greece without surcharge, just like in Barcelona. If you have 30 GB in your plan, you have 30 GB in Athens. Greece is fully included in the list of 33 countries in the European roaming area.
Now, the fine print does exist: it's called the fair use policy. Operators can limit your gigabytes outside Spain to prevent someone from contracting a Spanish plan and living permanently abroad. As of January 1, 2026, the limit is calculated as follows: monthly cost without VAT, divided by 1.10, multiplied by 2.
An example with real numbers from an average plan: you pay €20 per month with VAT, or €16.53 without VAT. Divide by 1.10 and multiply by 2: about 30 GB usable in Greece. With a €10 plan, the calculation drops to about 15 GB. If you exceed the cap, the operator can charge you up to €1.10/GB extra in 2026 (€1/GB from 2027). It's not a disaster, but it's good to know before uploading videos from the caldera.
You can find the full breakdown of rates and surcharges in my guide on how much international roaming costs.
When roaming DOESN'T work (and buying data IS worth it)
If European roaming is included, why buy data separately? Because there are four specific situations where the equation breaks down, and they are more common than they seem.
- Plans with little data. If you have 5 or 10 GB per month, your European cap will be 7-15 GB, and in 10 days with maps, photos, and Reels, that flies by. Worse: you use it all up and return home with no data for the rest of the month.
- Old or prepaid plans. Some legacy plans and many prepaid plans apply ridiculous roaming limits or charge separately. Check your contract; don't assume anything.
- Non-EU travelers. If you travel with a post-Brexit UK, Swiss, Latin American, or US number, "Roam Like At Home" doesn't cover you, and roaming in Greece can cost you several euros per megabyte.
- Intensive use or long stays. If you work remotely, share your connection with your laptop, or stay for more than 4 months: the fair use policy also limits continuous stay outside Spain.
In any of these cases, buying data separately stops being a luxury and becomes the sensible decision. There's a fifth reason, less technical but very real: arriving home with your plan intact. If you want the side-by-side comparison, I elaborate on it in eSIM vs. roaming.
Hotel Wi-Fi: what it’s good for and what it’s not
Greece is surprisingly well-served with free Wi-Fi. Hotels, apartments, taverns, cafes, and even many organized beaches offer it in exchange for a purchase, and Athens airport, Piraeus, and ferry terminals have public Wi-Fi. As a backup network, it's excellent and costs nothing.
The problem is that Wi-Fi solves the wrong moment. Think about when you really need internet: when you get off the plane and look for the bus to Syntagma. When the taxi drops you off at the wrong spot in Fira. When the ferry changes docks at the last minute. In all those moments, you are not sitting in a hotel; you are on the street with luggage.
Add two more problems. The first, actual speed: on small islands, the accommodation's Wi-Fi runs on a saturated link and drags during high season. The second, security: open public networks are the worst place to access your bank. If you use them, do so with a VPN.
My advice: use Wi-Fi for heavy and planned tasks—offline maps, photo backups, long video calls—and have mobile data for everything else. If you were thinking of a portable router, read eSIM vs. pocket Wi-Fi first: carrying an extra device every night is less convenient than it seems.
Local Greek SIM: Cosmote, Vodafone, and Nova
Greece has three operators with their own network. Cosmote (part of the Deutsche Telekom group) is the clear leader: best geographical coverage, around 85% of the territory, and the highest speeds, with averages of 350 Mbps on 5G. Vodafone Greece follows with around 200 Mbps and coverage heavily focused on tourist areas. Nova (formerly Wind) closes the podium with around 150 Mbps and a decent network in island capitals but weaker outside them.
Buying a prepaid SIM is easy: there are official stores at Athens airport, in ports, and in almost any large town. Prices are good—a COSMO CARD costs around €14 with about 25 GB, and Vodafone packs range from €18 to €27 with 25 GB or unlimited data—.
The cost isn't the price; it's the time and friction. In Greece, SIM registration is mandatory: passport and form. That means queuing at the airport just when you want to rush out, or looking for an open store—be careful with Sundays and long siestas on the islands. Plus, you change numbers, so you lose bank SMS. If this is the debate, I break it down in eSIM vs. local SIM.
eSIM: how it works and which network it connects you to
An eSIM is a digital SIM already soldered inside your phone. Instead of inserting a physical card, you download a profile with a QR code and you're all set. The important thing for Greece is this: the eSIM doesn't create a new network; it relies on the same antennas as Cosmote, Vodafone, and Nova. That means the coverage you'll get is exactly that of the Greek operators.
The practical advantages are three. First: you activate it before leaving Spain, with your home Wi-Fi and no rush, so you land in Athens with data while everyone else is looking for a SIM store. Second: you keep your Spanish number because your physical SIM remains inside, and you only deactivate its data. Third: no paperwork, no passport, no deposit.
The requirements are simple: a compatible phone (iPhone XS or later, Pixel 3 onwards, Galaxy S20, and almost all recent mid-range models) and it must be unlocked. If you're unsure, dial *#06#: if an EID number appears, your phone supports it. I explain it step-by-step in what an eSIM is.
An honest nuance: most tourist eSIMs are data-only. They don't come with a Greek number for traditional voice calls. In 2026, that rarely matters—you call via WhatsApp, book online—but if you need to call a Greek landline, keep it in mind.
Direct comparison of the four options
With everything on the table, here's the complete picture. I've added the estimated cost for a 10-day trip, which is the typical duration for a combined Athens + islands trip.
| Option | Cost (10 days) | Main advantage | Weak point |
|---|---|---|---|
| EU Roaming (Spanish plan) | €0 (included) | No action needed, works automatically | Fair use policy limit; uses up monthly data |
| Hotel and cafe Wi-Fi | €0 | Free and no setup required | Only when stationary; slow in high season |
| Local Greek SIM | €14-27 | Best price per gigabyte for long stays | Passport, queue, change of number |
| Data eSIM | ~€10-25 | Activated before flying, keep your number | Requires compatible and unlocked phone |
My blunt summary, and this is where I truly take a stand:
If your Spanish plan has 30 GB or more and you're traveling for a week, don't buy anything: just use European roaming. If you have less than 15 GB, travel for more than ten days, work from your phone, or your number is not from the EU, buy data separately. That's the entire decision.
The local SIM only wins in one scenario: stays of several weeks or months, where the price per gigabyte eventually outweighs convenience. For a normal tourist trip, the friction of registration and changing numbers is more impactful than the few euros in difference.
Real coverage: Athens, Santorini, Mykonos, and Crete
Greece is not a uniform block. Coverage varies greatly depending on where you are, and it's wise to adjust expectations island by island.
| Destination | Expected coverage | What to keep in mind |
|---|---|---|
| Athens | Almost total 5G (99% with Cosmote) | Excellent; only the metro has dead zones |
| Santorini | Very solid 4G/5G in Fira and Oia | Saturation at sunset in Oia: thousands of phones simultaneously |
| Mykonos | Good 4G/5G in Chora and large beaches | Drops in southern coves and during large parties |
| Crete | Very good on the north coast (Chania, Heraklion) | Interior gorges and mountains: no signal |
| Small Cyclades | Irregular outside villages | Cosmote is the only one with reliable coverage |
The practical lesson is that the problem in Greece is almost never the country itself: it's the geography and overcrowding. In Oia, at sunset, thousands of people pointing their phones at once can bring down any cell tower; no eSIM or local SIM can fix that. And in the Samaria Gorge or the interior of Naxos, there simply isn't an antenna to connect to.
That's why my golden rule is the same, no matter your connection option: download offline maps for each island on Google Maps and save screenshots of your bookings and ferry tickets to your camera roll. It's free, takes two minutes, and saves you from the one problem that can ruin a day of travel.
Inter-island ferries: the blind spot no one tells you about
This is the section that can save you the most money, and almost no guide mentions it. When the ferry moves away from the coast, your phone loses connection to land-based antennas. Then one of two things happens.
The good: you lose data for a while, and that's it. On short routes between Cycladic islands—Santorini to Ios, Mykonos to Paros—coverage is irregular because you never move too far from land.
The bad: your phone connects to a maritime network, those onboard antennas that route via satellite. And here comes the shock: maritime networks are expressly excluded from the European roaming regulation (EU Regulation 2022/612). You're not in Greece; you're "at sea." Actual prices range from €3 to €10 per megabyte: a short video can cost you more than €18, and a photo sent to you automatically via WhatsApp, about €7. Without even touching your phone.
How to protect yourself on any long crossing—Piraeus to Crete, Piraeus to Rhodes, any overnight trip—: activate airplane mode as soon as you set sail and only use the ship's Wi-Fi if available. And download music, podcasts, and maps before boarding.
Here's a little-known advantage of tourist data plans: since they operate based on agreements with specific terrestrial networks, they do not connect to the onboard maritime network and cannot generate a surprise charge at sea.
How much data you actually need
The million-dollar question, and the one that's hardest to answer. Almost all guides push you to buy 20 GB "just in case." The reality of a tourist trip is more modest: you spend your day walking, eating, and at the beach, not watching Netflix.
| Traveler profile | Daily consumption | For 10 days |
|---|---|---|
| Basic (maps, WhatsApp, some emails) | ~300 MB | 3 GB |
| Normal (above + social media and photos) | ~500-700 MB | 5-7 GB |
| Intensive (Reels, stories, streaming, music) | ~1-1.5 GB | 10-15 GB |
| Digital nomad (tethering to laptop) | 2 GB or more | 20 GB+ |
To calibrate: Google Maps navigating uses about 5 MB per hour, a trifle. WhatsApp with texts and photos, about 100 MB per day. What really drives up the bill is always video: an hour of Instagram or TikTok eats up between 600 MB and 1 GB, and an HD series, 3 GB per hour.
My honest recommendation for a week or ten days in Greece is 5-10 GB: that will be more than enough. If you upload stories daily, go up to 15 GB. Save streaming for hotel Wi-Fi, and you'll see your consumption plummet. Buying 50 GB for seven days is a waste of money, and anyone who tells you otherwise isn't being truthful.
Frequently Asked Questions
Does my Spanish plan work in Greece without extra charges?
Yes. Greece is in the EU, so "Roam Like At Home" obliges your operator to provide calls, SMS, and data without surcharge. The only limit is the fair use policy: in 2026, it's your plan's price without VAT divided by 1.10 and multiplied by 2.
So why do I need an eSIM in Greece?
Only in four cases: if your plan has little data (less than 15 GB), if it's an old or prepaid plan with strange limits, if your number is not from the EU (UK, Switzerland, Latin America, USA), or if you tether your laptop. With 30 GB and a week's travel, you don't need one.
Will I have coverage on inter-island ferries?
Sometimes. On short trips between the Cyclades, there's intermittent signal from land. On long crossings, be wary: your mobile might connect to the ship's maritime network, which is excluded from European roaming and costs between €3 and €10 per megabyte. Turn on airplane mode when you set sail.
Is there good coverage in Santorini and Mykonos?
Yes, both have solid 4G and 5G in the main areas. The problem isn't coverage but saturation: in Oia at sunset, with thousands of mobiles connected at once, the network is slow. This isn't your provider's or your plan's fault.
How many gigabytes do I need for 10 days in Greece?
Between 5 and 10 GB for normal use: maps, WhatsApp, social media, and photos. If you upload stories daily, estimate 15 GB. If you share your connection with a laptop, 20 GB or more. Save streaming for the hotel's Wi-Fi.
Do I need my passport to buy a Greek SIM?
Yes. In Greece, prepaid card registration is mandatory by law: you must present your passport or ID and fill out a form in the store. This is the main reason why many travelers choose the digital option, without paperwork.
Which Greek operator has the best coverage in the islands?
Cosmote, no question. It covers about 85% of the territory and is the only one with reliable signal in the smaller Cyclades and remote Dodecanese. Vodafone concentrates its network in tourist areas and Nova is the most limited outside the island capitals.
Can I keep my Spanish number while using Greek data?
Yes, and that's the main advantage of the digital format. Your physical SIM remains inside, receiving calls and SMS from the bank; you just deactivate its mobile data. With a physical local SIM, you would have to remove your card and would miss those notifications.
Conclusion
I'll break down the decision to the bare minimum. Check your plan before buying anything: if you have 30 GB or more and are going to Greece for a week, European roaming covers you and you don't need to spend a euro. If you have little data, are traveling for more than ten days, work from your mobile, or your number is not European, buying data separately is cost-effective. And whatever you do, two things: download offline maps of each island and turn on airplane mode as soon as the ferry leaves port, as that's where you really lose money.
If your case is the second, the PuraSIM eSIM for Greece gives you data ready before boarding, on the Greek operators' network, without a passport, without queues, and keeping your Spanish number. You activate it from your couch at home and land in Athens with working internet. Have a good trip.
