

If your Balkans trip crosses more than one border (Dubrovnik to Kotor to Tirana, say, or Belgrade to Skopje to Thessaloniki), a single regional eSIM like co:sim's europe-7 plan (from $4.99) covers Serbia, Bulgaria, Montenegro, Croatia, Albania, Greece, and North Macedonia without swapping SIMs at every crossing. If you're staying inside one country the whole trip, that country's own co:sim plan is usually cheaper per gigabyte. This guide walks through the real numbers for both cases, what the regional bundle actually includes, and how coverage holds up country by country, so you can tell which trip you're actually taking.
Three things decide whether a regional plan or a single-country plan is the better buy:

co:sim's europe-7 regional eSIM (catalog code EU-7) covers Serbia, Bulgaria, Montenegro, Croatia, Albania, Greece, and North Macedonia on 15+ partner networks, all rated 4G or 5G. Pricing runs from a $4.99 500MB/day starter to a $104.99 20GB/30-day plan, all rechargeable from the account dashboard mid-trip.
At the entry tier, the math is straightforward: co:sim's regional 500MB/day plan is $4.99 for all seven countries. Buying the cheapest single-day plan separately in each of the seven (the way you'd have to if you bought country by country) comes to $11.93 combined, and that's before counting the hassle of installing and activating seven separate eSIMs.
At a more realistic mid-trip tier, here's what the same 3GB/30-day allowance costs bought regionally versus country by country (current prices, fetched from co:sim's live catalog):
Buying all seven separately gets you more total data (21GB vs. 3GB) for a higher combined price, but that data is split into seven pools that don't travel with you: the Serbian gigabytes are useless once you cross into Montenegro. For a genuine multi-country itinerary, the regional bundle is both cheaper and the only version of "3GB" that actually follows you across every border. If you're visiting just one or two of these seven, buying that country's own plan is the better deal on a pure cost-per-GB basis — honestly, don't buy the regional bundle for a trip that never leaves Zagreb.
It's tempting to assume an EU phone plan roams free everywhere in "Europe." It doesn't. The EU's "Roam Like at Home" rule, which eliminates roaming charges within the bloc, applies strictly to the 27 EU member states plus Iceland, Liechtenstein, and Norway (European Parliament). Of co:sim's seven europe-7 countries, only Croatia, Bulgaria, and Greece are EU members (European Union); Serbia, Montenegro, Albania, and North Macedonia are not, so an EU SIM's free-roaming benefit stops the moment you leave one of those three.
Croatia is also inside the Schengen passport-free zone, which it joined in January 2023, while Bulgaria only joined Schengen's air and sea borders in 2024 (European Parliament), a mix of EU, Schengen, and neither that trips up plenty of travelers assuming "the Balkans" behaves like one roaming zone. A data-only eSIM like co:sim's sidesteps the question entirely: the plan covers all seven regardless of which are in the EU, Schengen, both, or neither.

co:sim's europe-7 plan runs on 15+ partner networks, all 4G or 5G, with at least one 5G partner in every covered country as of this writing:
Coastal and capital-city coverage is consistently strong across all seven — Dubrovnik, Kotor Bay, Tirana, Belgrade, Skopje, Sofia, and Athens all sit on 5G-rated partner networks. Coverage thins out, as it does with any carrier, in mountainous interior stretches (inland Montenegro, rural North Macedonia) where a single tower may serve a wide valley.
co:sim's europe-7 regional eSIM (catalog code EU-7) covers seven countries: Serbia, Bulgaria, Montenegro, Croatia, Albania, Greece, and North Macedonia, on 15+ partner networks rated 4G or 5G. It does not cover Bosnia and Herzegovina or Kosovo, which sit outside this particular bundle: if your route includes either, check co:sim's individual country pages or a broader European regional plan before you go. Plans run from $4.99 (500MB/day) to $104.99 (20GB/30 days), and the data allowance is shared across all seven countries rather than split per country, so it moves with you as you cross borders. The eSIM is data-only, so it won't include a phone number for calls or texts — pair it with an app like WhatsApp or your home SIM for those.
It depends on how many of the seven you're actually visiting. For a single-country trip, that country's own co:sim plan is cheaper per gigabyte; buying the regional bundle for a trip that only touches Croatia, for instance, doesn't make sense. But once you're visiting three or more of the seven countries, the math flips: a co:sim europe-7 3GB/30-day plan costs $21.99 and works in all seven, while buying the equivalent 3GB/30-day plan separately in even three of those countries typically costs more combined, and each pool is locked to one country instead of following you across the border. The regional bundle also means installing one eSIM instead of several, which matters in practice: some phones cap how many eSIM profiles they can store active at once, and swapping the active data line every time you land somewhere new is its own source of missed messages and failed map loads right when you need them most.
No, and that's the entire point of a regional eSIM. Once co:sim's europe-7 plan is installed and connected in any of the seven countries, it stays connected as you cross into the others; the underlying partner network switches automatically in the background, the same way your phone picks a new tower within a single country. You don't reinstall, re-scan a QR code, or do anything at the border, and you don't lose your data allowance mid-transfer the way you would swapping physical SIM cards. A single-country eSIM, by contrast, simply stops working the moment you leave that one country's coverage area, so you'd need to buy and install a fresh eSIM (or reactivate your home SIM's roaming) at every crossing, an easy thing to forget until your maps app stops loading on the highway.
No, and this catches out plenty of travelers. The EU's roaming-free rule ("Roam Like at Home") only applies within the EU and the EEA (Iceland, Liechtenstein, Norway), under a regulation the European Parliament confirms runs through 2032. Of the seven europe-7 countries, only Croatia, Bulgaria, and Greece are EU members; Serbia, Montenegro, Albania, and North Macedonia are not, so an EU SIM reverts to standard, often expensive, international roaming rates the moment you cross into one of those four. It isn't a matter of your carrier being unusually strict either; the free-roaming rule simply has no legal reach outside the EU and EEA, so no EU carrier can extend it there even if it wanted to. A dedicated data-only eSIM covering all seven, like co:sim's europe-7 plan, avoids that gap entirely and charges the same whether the country you land in happens to be in the EU or not.
Yes, on the reloadable tiers. co:sim's europe-7 plans at 1GB/7-days and above are reloadable from the account dashboard without reinstalling the eSIM, so you can add another block of data mid-trip the moment you're running low rather than hunting for a new QR code with a weak connection. The 500MB/day and 2GB/day tiers work differently: they're daily allowances (non-reloadable or auto-renewing per day) rather than a fixed pool you top up, so they suit a short trip better than a long one. Each plan page on co:sim's site states plainly which type a given tier is, along with its install deadline and billing-start rule, before you buy, so there's no guessing which behavior you're getting once you land. If you're unsure how much data a multi-country Balkans trip actually needs, the mid-tier 3GB or 5GB/30-day plans are the safer starting point over the smallest daily option.
A regional eSIM only pays off once your itinerary actually leaves one country. If your route stays inside a single country the whole time, browse co:sim's full destination list for that country's own plan instead.
co:sim's europe-7 Balkans regional eSIMMexico
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| Coverage | Data | Validity | Price |
|---|
| co:sim europe-7 (regional) | 3GB, shared across all 7 countries | 30 days | $21.99 |
| Serbia only | 3GB | 30 days | $7.99 |
| Montenegro only | 3GB | 30 days | $7.99 |
| Albania only | 3GB | 30 days | $7.99 |
| North Macedonia only | 3GB | 30 days | $9.99 |
| Croatia only | 3GB | 30 days | $4.99 |
| Greece only | 3GB | 30 days | $4.99 |
| Bulgaria only | 3GB | 30 days | $4.99 |
| Sum of all seven separately | 21GB total, but locked one country at a time | 30 days each | $48.93 |