I'm going to start where almost no one starts: if you have a normal Spanish mobile plan, you probably already have internet in Greece included. Greece is part of the European Union, and that changes the entire conversation. Even so, every summer I see travelers burn through their data plan in three days in Mykonos or get a shock of hundreds of euros on a ferry. Here I compare all the real options—European roaming, hotel Wi-Fi, Greek local SIM, and eSIM—and tell you honestly when each one is worth it.
The four ways to connect 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 Greek prepaid 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 fails spectacularly in another. European roaming is unbeatable if your plan has plenty of data. Wi-Fi is free, but ties you to one location. A local SIM offers the best price per gigabyte if you stay for weeks, at the cost of losing your phone 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 having set up dozens of data configurations for trips across Europe, is simple: first look at what you already have, then what you're going to consume, and only then decide if you need to buy something. If you prefer to get straight to the point with the digital option, I have a specific guide for the eSIM for Greece with activation steps.
Roaming with your Spanish plan: what's really included
I have to be honest here, 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 on 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, which is €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 a complete breakdown of rates and surcharges in my guide on how much international roaming costs.
When roaming is NOT enough (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 limited data. If you have 5 or 10 GB per month, your European cap is 7-15 GB, and in 10 days with maps, photos, and Reels, that flies by. Worse: you use it up and return home without data for the rest of the month.
- Old or prepaid plans. Some legacy plans and many prepaid options apply ridiculous roaming limits or charge separately. Check your contract; don't take it for granted.
- Travelers from outside the EU. If you're traveling with a post-Brexit British, Swiss, Latin American, or American 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 a laptop, or stay for more than 4 months, the fair use policy also limits continuous stays 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: returning home with your plan intact. If you want a direct comparison, I delve into 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, tavernas, 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 doesn't cost a euro.
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 in the wrong place in Fira. When the ferry changes docks at the last minute. In all those moments, you're not sitting in a hotel; you're on the street with a suitcase.
Add two more problems. The first, actual speed: on small islands, accommodation Wi-Fi runs on a saturated link and crawls during peak 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 about a portable router, read eSIM vs. pocket Wi-Fi first: charging an extra device every night is less convenient than it seems.
Greek local SIM: Cosmote, Vodafone, and Nova
Greece has three operators with their own network. Cosmote (part of Deutsche Telekom group) is the clear leader: better geographic 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) rounds out 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 a queue at the airport just when you want to rush out, or searching for an open store—beware of Sundays and long siestas on the islands. Plus, you change your number, so you lose bank SMS messages. 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 that comes pre-soldered inside your mobile. Instead of inserting a physical card, you download a profile with a QR code and you're ready. What's important for Greece is this: the eSIM doesn't create a new network; it relies on the same antennas of Cosmote, Vodafone, and Nova. That means the coverage you'll get is exactly that of the Greek operators.
There are three practical advantages. First: you activate it before leaving Spain, with 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 stays inside and you only deactivate its data. Third: no paperwork, no passport, no deposit.
The requirements are simple: a compatible mobile (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 mobile 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, this 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 laid out, here's the complete picture. I've added the estimated cost for a 10-day trip, which is the typical duration for an Athens + islands combination.
| Option | Cost (10 days) | Main Advantage | Weak Point |
|---|---|---|---|
| EU Roaming (Spanish plan) | €0 (included) | No action needed, works automatically | Fair use limit; consumes your monthly data |
| Hotel and cafe Wi-Fi | €0 | Free and no setup | Only when stationary; slow during peak season |
| Greek local 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 straightforward summary, and this is where I truly commit:
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 mobile, or your number is not from the EU, buy data separately. That's the entire decision.
A 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 outweighs the few euros 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 good to adjust expectations island by island.
| Destination | Expected Coverage | What to Consider |
|---|---|---|
| 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 mobiles at once |
| Mykonos | Good 4G/5G in Chora and large beaches | Drops in southern coves and at massive parties |
| Crete | Very good on the north coast (Chania, Heraklion) | Gorges and mountains inland: no signal |
| Small Cyclades | patchy 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 will overwhelm 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 regardless of your connection option: download offline maps for each island in Google Maps and save screenshots of your reservations 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 mobile loses terrestrial antennas. Then one of two things happens.
The good: you lose data for a while, and that's it. On short routes between the Cyclades—Santorini to Ios, Mykonos to Paros—there's patchy coverage because you never get too far from land.
The bad: your mobile connects to a maritime network, those on-board antennas that route via satellite. And here's the hit: maritime networks are expressly excluded from European roaming regulations (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 over €18, and a photo that arrives unsolicited 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 journey—: 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: because they operate based on agreements with specific terrestrial networks, they don't connect to the on-board maritime network and cannot generate a surprise charge at sea.
How much data do you really 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 email) | ~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 gauge: 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 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'll be more than enough. If you upload stories daily, go up to 15 GB. Reserve 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 sells it to you that way isn't being truthful.
Frequently asked questions
Does my Spanish plan work in Greece without paying anything?
Yes. Greece is in the EU, so "Roam Like At Home" requires your operator to provide calls, SMS, and data without surcharge. The only limit is the fair use policy: in 2026, the price of your plan without VAT divided by 1.10 and multiplied by 2.
So why would I need an eSIM in Greece?
Only in four cases: if your plan has limited data (less than 15 GB), if it's an old or prepaid plan with unusual limits, if your number is not from the EU (UK, Switzerland, Latin America, USA), or if you share your connection with a laptop. With 30 GB and a week of travel, you don't need one.
Will I have coverage on the inter-island ferry?
Intermittently. On short trips between the Cyclades, there is intermittent signal from land. On longer 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. Put your phone 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 at once, the network slows down. This is not your operator's or 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 SIM card registration is mandatory by law: you must present your passport or ID and fill out a form at the store. This is the main reason why many travelers choose the digital option, with no paperwork.
Which Greek operator has the best coverage in the islands?
Cosmote, without a doubt. It covers around 85% of the territory and is the only one with a reliable signal in the small Cyclades and remote Dodecanese. Vodafone concentrates its network in tourist areas, and Nova is the most limited outside of 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 simplify the decision for you. 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 separate data is cost-effective. And whatever you do, two things: download offline maps for each island and put your phone on airplane mode as soon as the ferry leaves the port, 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 network of Greek operators, without a passport, without queues, and keeping your Spanish number. You activate it from your sofa at home and land in Athens with working internet. Have a good trip.
