Our approach to roaming advice

Carrier roaming rates are sourced directly from the official international plan pages of AT&T, Verizon, T-Mobile, Vodafone UK, EE, and Three UK. We access each carrier's rate card through their public-facing website using the same path a customer would follow when researching a trip. No reseller databases. No third-party aggregators. No estimates.

AT&T International Day Pass pricing covers 210+ destinations at a flat $12/day rate. T-Mobile Magenta plans include free international data at reduced 128 Kbps speeds in 215+ countries. Go5G Plus customers get 5GB of free high-speed internationally. The $10/day International Pass unlocks LTE for all other plans. Verizon TravelPass costs $12/day (down from $14) with a 5GB high-speed cap, then 3G speeds. We record the standard plan rates for a traveler on a base-tier domestic plan — not a premium tier that most customers do not hold.

For Vodafone UK, EE, and Three UK, rates changed materially after UK carriers ended automatic EU roaming inclusions. We track both the EU roaming rate and the rest-of-world rate separately because the gap is large and destination-specific. A traveler going to France faces a different pricing landscape than one going to Thailand. Three UK ended free Go Roam for new customers in October 2021 and raised EU rates again in December 2025. EE charges per calendar day, not a 24-hour rolling period. We note these plan-era distinctions explicitly so travelers know which rate applies to their account.

Retired plans are flagged but not removed from our database. AT&T Passport was retired on August 12, 2021. We retain the record to answer traveler questions but exclude retired plans from active cost comparisons and savings calculations.

Carrier rates are re-verified on the first Monday of each month. Any carrier that announces a rate change through a press release or customer communication triggers an immediate re-check, regardless of the monthly schedule. We receive carrier press releases through RSS and email subscriptions to each carrier's newsroom.

Every savings figure on Roaming Advice follows one formula: carrier daily rate multiplied by trip days, minus eSIM plan price, equals savings. We express this as a dollar amount and a percentage.

Example: AT&T charges $12 per day in Japan. A 7-day trip costs $84 on AT&T roaming. The cheapest eSIM for Japan at 5 GB costs $9. Savings: $75, or 89%.

We use the carrier's standard day-pass rate as the baseline. Travelers who have not pre-purchased a day pass will pay per-kilobyte overage rates — far higher than the day-pass figure. We do not use those rates in savings calculations because they represent an edge case, not typical usage. The day-pass rate is what a prepared traveler actually pays.

When a carrier offers a weekly international plan at a discounted rate compared to 7 individual day passes, we use the weekly plan price in the savings calculation. We always use the lowest available carrier price so our savings figures are conservative, not inflated.

eSIM plan prices used in the calculation are the cheapest available plan at the specified data volume on the day of the weekly price check. We pull from multiple providers and use the lowest price across all of them.

The roaming savings calculator on each country page lets travelers enter their carrier, their home country, and their trip length. The calculator returns the carrier's cost for that trip and the cheapest eSIM alternative, expressed as a daily rate, a total trip cost, and a savings amount.

Carrier rates in the calculator are the same figures used in the static savings tables — sourced from official rate cards and re-verified monthly. The calculator does not use estimated or interpolated rates. If a carrier's rate for a specific country is not in our verified database, that carrier does not appear as an option for that destination.

eSIM prices in the calculator are updated weekly from provider checkout pages. The calculator always uses the most recent verified price, not a cached figure from the last time the page was built. When a provider changes its price between weekly checks, the calculator reflects the update at the next scheduled Friday refresh.

Trip-length calculations use calendar days, not 24-hour periods. A traveler arriving on Monday and leaving the following Sunday pays for 7 days under most carrier day-pass models, regardless of what time they arrive or depart. The calculator uses the same convention.

Every eSIM provider we recommend is purchased and tested on four devices covering the three major platforms travelers use. Devices are factory-reset between providers so no carrier profile carries over. Roaming behavior is tested by activating the domestic SIM first, then switching to the eSIM abroad to measure real handoff timing.

Each provider is tested across the same 12 countries. We run 5 consecutive Ookla Speedtest readings per session and report the median value. Tests cover four location types: city center, suburban area, transit corridor (intercity rail or highway), and the primary international airport.

Speed tests run during two time windows per location: peak hours (12:00-14:00 local) and off-peak hours (06:00-08:00 local). This captures network congestion patterns that a single midday test would miss. Results are cross-referenced against Ookla Speedtest Intelligence quarterly datasets.

Activation tests begin the moment payment confirms. We measure the time to the first successful data packet on the target network on all four test devices. We report the slowest result across devices, because that is the number a traveler is most likely to experience.

Data verification runs monthly. Provider pricing is checked against live checkout pages. Carrier roaming rates are re-verified against official rate cards. Coverage maps are cross-referenced against GSMA Intelligence data.