eSIM, local SIM or roaming: a decision by country and trip length

Three options connect a phone abroad: keep the home plan and roam, buy a local SIM, or install a travel eSIM. The right one depends on four facts about the trip: where it goes, how long it lasts, what the phone supports and whether a laptop needs a hotspot. This guide turns those facts into a decision. It rests on official rules where rules exist: the European Commission on roaming in the EU and EEA, and government or regulator pages on SIM registration in the countries where one could be confirmed.

Prices are left out. Plan prices change often and no official source publishes travel eSIM listings, so no price is quoted for any provider. Providers are named Provider A to D while partner links are set up, and the plan types in the last table are described in general terms.

Work through these in order, because the first one removes the most options.

1. Where the trip goes. Inside the EU and EEA the home plan may already be the answer. Outside, nothing in the EU rules sets a price, and each operator's rate card applies. 2. How long it lasts. A daily roaming charge multiplies by the number of days, while an eSIM or local SIM has a fixed amount for a block of days. A stay of several months brings registration rules into play. 3. What the phone supports. An eSIM needs a phone that supports it and is not locked to the home carrier. Both are questions for the carrier, and a locked phone can accept a profile and then refuse to connect. 4. Hotspot and phone number. Tethering a laptop is a plan-level rule stated on the listing or in the contract. A local number matters if calls, delivery apps or bank codes by SMS are part of the trip.

Roam like at home switches on automatically in the 27 EU countries and in Iceland, Liechtenstein and Norway. Since 1 January 2026 it also covers Ukraine and Moldova. Calls, texts and data used there are charged as they are at home, and the Commission says the quality of service, such as speed and 5G access, should match home where the network allows it. The regime does not apply in the UK, though the Commission notes that some operators have kept the benefits, and Switzerland is not on the list.

These pages describe the rule from the viewpoint of a subscriber of an operator in the EU or EEA who travels away from the country of the subscription. For a plan from an operator elsewhere, such as the US or the UK, they set no price in Europe, and that carrier's own rate card is the source.

Fair use is the part that changes a trip plan. Operators may apply a data limit to unlimited or very cheap plans. The roaming volume must be at least twice the amount obtained by dividing the monthly price excluding VAT by the regulated wholesale cap, and the operator must warn at 80% of the limit. Past the limit, a capped surcharge applies. Your Europe gives the cap as €1.30 per GB in 2025, falling to €1 per GB from 2027. Operators must also warn at €50 and at €100 of extra charges in a month and cut off at €50 unless you opt out.

For a short trip inside the zone on a plan from an operator there, the home plan is the baseline any other option has to beat: no install, no second line. The case for a travel eSIM inside the zone is narrower. It covers a plan with a low fair-use data limit, a plan that excludes roaming, or a stay long enough to trigger the four-month review.

Your Europe says the cost of roaming, particularly data, outside the EU and EEA can be expensive, and advises checking the cost with the provider before travelling. It also notes that many operators choose to extend their roam-like-at-home offers to other countries, so whether the destination is included is a line in the plan, not a given.

A home carrier's travel pass or day pass is the usual alternative to standard rates. Compare these items for the whole trip, and avoid reading only the daily figure: the daily charge, the number of days it lasts, the speed after the daily allowance, and whether hotspot is allowed. For a day or two, the simplicity of a pass has real value. Over a week or more, the daily charge multiplies and an eSIM listing with a fixed block of days is worth pricing against it.

A local SIM gives local rates and often a local number, and in many countries buying one involves identity checks. Rules are set country by country. Four could be confirmed on official pages.

Germany requires providers of prepaid mobile services to check the subscriber's data before activation against an identity document such as a passport. China sells SIMs at carrier service branches, and foreigners bring a passport or a Foreign Permanent Resident ID Card.

Vietnam's Ministry of Science and Technology announced that from 15 April 2026 all newly registered mobile subscriptions need facial biometric verification checked against national databases, and that a subscriber moving a SIM to a different device is asked to re-verify. The announcement does not say how this applies to foreign visitors, so the seller's counter is where to ask.

Turkey is a different case because the rule is about the phone. The telecom regulator's guide for devices brought from abroad says registration has to be done within 120 days of the entry date, requires a fee, and says registration is needed so the device can be used without problems. The guide does not say how a foreign eSIM profile is treated, so a stay of four months or longer is the point to ask the operator.

Registration rules in other countries, including Thailand, India and Japan for data-only SIMs, were not confirmed against an official page for this guide, so none is stated. Ask the carrier counter, the airport kiosk or the embassy before the trip.

Whatever the country, a local SIM asks for a few things in common. The phone has to be unlocked, a physical SIM needs a free slot or a second eSIM slot, and the passport has to be on hand at the counter, not in a checked bag. On a phone with a single physical slot the home SIM comes out while the local one is in, so any bank that sends codes by SMS needs a plan. Moving the local SIM between phones can trigger fresh verification in countries with device-change rules, as Vietnam's notice describes.

A travel eSIM is a data plan delivered digitally, so it is bought and installed before landing and skips the counter. It fits a specific set of trips: the phone supports eSIM and is unlocked, the trip lasts one to a few weeks, and the destination is one or two countries outside the home plan's zone. A regional plan can cover several countries with one profile, and the listing should state which countries it covers and whether hotspot is blocked on that plan.

It fits less well when a local number is needed, or when a stay of a month or more in one country can be served by a local plan whose total cost is lower. A data-only plan leaves SMS codes on the home line, so the home SIM stays active with data roaming switched off.

Listing terms vary, and these are the ones that change the outcome:

• The countries covered, and whether a regional plan pools data across them.

• The data amount, and the speed after any daily cap.

• The validity in days, and whether the count starts at install or at first connection.

• Whether hotspot is allowed.

• Whether a phone number is included, or only data.

• Top-up rules and what happens when the data runs out early.

The Japan eSIM guide shows how those terms differ across plan types for one destination.

The table maps common situations to the option that usually fits and the item to check first.

Install the profile over Wi-Fi at home, keep it switched off until landing, and turn data roaming on for that line only. Keep the home SIM on for calls and texts with its own data roaming off. Screenshot the install QR code and the access details before departure.

The table lists the four plan types described in the Japan eSIM guide, with the terms to check on each listing. No price or availability was checked for it.