Our Research Method
PrepaidSIM is a price comparison engine for eSIM data plans. Five providers. 185+ countries. Weekly API polling. USD normalization via ECB rates. Plans ranked by cost-per-gigabyte. No paid placements. The cheapest plan wins.
Price Summary:
PrepaidSIM polls 5 providers every Monday. All prices convert to USD at ECB mid-market rates. Plans rank ascending by $/GB. Ties break by data volume, then validity. Price errors correct in the next Monday polling cycle. No paid placement. Prices verified against provider websites. Speed data source: Ookla Speedtest Intelligence.
Weekly price collection
Every Monday at 00:00 UTC, automated scripts poll public APIs and storefronts for all 5 tracked providers: HelloRoam, Airalo, Holafly, Saily, and Nomad. The five providers were selected because they collectively offer active plans in the largest number of the 185 countries PrepaidSIM tracks. Each poll captures plan name, data allowance in GB, validity in days, listed price in provider currency, supported networks per country, and top-up availability. Raw API responses are archived for 90 days before normalization so any discrepancy can be audited against the original source. If a provider changes their pricing page structure or API schema mid-week, the next Monday cycle picks up the change automatically. No user-submitted price data is accepted — all data originates from official provider channels only.
USD normalization
All prices convert to USD using the European Central Bank daily reference rate fetched at poll time. A plan listed in EUR, GBP, AUD, SGD, or any other currency gets converted at that day's mid-market rate. We never use cached exchange rates older than 24 hours. Reconversion runs on every weekly cycle, so a provider that lists in a weakening currency may appear cheaper in USD even if their local price held steady. Providers that list prices in USD natively skip the conversion step. The raw plan price in the original provider currency is always stored alongside the USD equivalent so the conversion can be audited at any time.
Per-GB calculation
For every plan, cost-per-gigabyte equals USD price divided by data allowance in gigabytes. Example: a $9.40 plan with 10 GB = $0.94/GB. Plans rank ascending by this figure within each country page. Unlimited plans are excluded from per-GB rankings because the denominator is undefined. They appear in a separate section with a daily-rate equivalent calculated as total price divided by validity in days, which allows a fair comparison against fixed-data plans. Plans with non-standard units (MB, TB) are converted to GB before the per-GB figure is calculated. Plans with zero listed data are excluded from all ranking tables.
Ranking method
Countries rank by their cheapest available plan's $/GB, ascending. Within a country page, all plans from all providers list cheapest-first. Ties on $/GB break first by higher data volume (more data for the same rate is better), then by longer validity (more days for the same rate is better). Plans with identical $/GB, data volume, and validity period appear in alphabetical provider order. The cheapest plan always occupies rank #1 regardless of provider. No provider can buy a higher rank position, and no provider relationship affects sort order.
30-day trend tracking
PrepaidSIM stores 12 rolling weeks of historical $/GB snapshots per plan. The trend arrow on each country page compares the current week's cheapest $/GB against the reading from exactly 30 days prior. A downward arrow means the cheapest available plan for that country got cheaper on a per-GB basis. An upward arrow means it got more expensive. A dash means the rate held within a 2% tolerance band, treated as flat. Plans that appeared or disappeared from a provider's catalog within the window are noted. The trend reflects the cheapest plan available each week, not a single provider's price movement. A country can show a downward trend if a new cheaper plan entered the market, even if existing plans held their price.
Provider scoring
Each provider receives a composite score across four price-weighted categories. Per-GB Rate (40% weight): median $/GB rank position across all 185 tracked countries. Plan Range (20%): breadth of data tiers, validity periods, and regional or multi-country options. Hidden Costs (20%): whether top-up markups, tethering fees, checkout surcharges, or activation-timing traps inflate the real cost beyond the headline price. Value Retention (20%): refund window length, top-up rate consistency, and whether unused data carries any residual value. Price-related factors account for 80% of the total score because per-GB cost is the dominant purchase factor for travelers using this tool.
Independence and disclosure
Rankings are 100% price-driven. No provider pays for placement, a higher listing position, a badge, or any editorial treatment. PrepaidSIM uses affiliate links for some providers and discloses this on every comparison page. Affiliate commission rates are not disclosed to the team that builds or maintains rankings, and have no bearing on any ranking calculation. A provider offering a higher affiliate commission still ranks below a cheaper competitor. The cheapest plan wins, always. This policy is non-negotiable and has been in place since PrepaidSIM launched.
Historical accuracy and corrections
PrepaidSIM targets a data error rate below 1% of published plan prices at any given time. If a price is wrong, stale, or a plan no longer exists, email data@prepaidsim.net. Include the country, provider, and the correct plan data. Corrections are verified against the provider's official storefront and published in the next Monday polling cycle. All correction events are logged internally. If a systematic error is found, such as an exchange rate calculation bug or a provider API schema change that broke parsing for a subset of plans, all affected pages update in the same Monday cycle.
Score categories and weights
Each provider receives a score out of 10 based on the four price-weighted categories below. Per-GB Rate carries 40% of the total weight because it is the dominant purchase factor. The remaining 60% covers plan range, hidden costs, and value retention. Scores update weekly with the pricing cycle.
Providers and polling schedule
PrepaidSIM tracks five providers: HelloRoam, Airalo, Holafly, Saily, and Nomad. These five account for the majority of the consumer eSIM market for travelers. Data pulls run every Monday at 00:00 UTC via provider public APIs and official pricing pages. No user-submitted data is accepted.
Raw API responses are archived for 90 days. This allows retroactive audits when a provider changes their plan structure or API schema. Every price visible on the site was verified within the last seven days by the automated polling system.
How we source airport data
Airport SIM and eSIM kiosk prices are tracked separately from provider digital plans. A plan purchased at an airport kiosk often costs 40–200% more than the same provider’s online price for the same destination. PrepaidSIM collects airport pricing data so travelers who arrive without a plan can make an informed decision at the kiosk.
Airport SIM prices come from two sources. Primary source: official airport operator websites and concession partner pages. The top 35 airports by international passenger volume are checked monthly. Secondary source: travel community reports from verified frequent travelers. Community-sourced prices are labelled separately from operator-verified prices and include the report date. Community data older than 90 days is removed from display.
Airport prices are not included in the per-GB ranking algorithm. They appear as a reference comparison alongside the online plan table so travelers can see the price premium they are paying for on-arrival convenience. No airport operator or kiosk vendor has paid for placement or listing on PrepaidSIM.
No paid placement
PrepaidSIM earns revenue through affiliate commissions. When a plan is purchased through a link on this site, a percentage of the sale goes to PrepaidSIM. Affiliate commission rates vary by provider and are not shared with the team that builds or maintains rankings.
Providers cannot pay for a higher ranking, a badge, or placement above cheaper competitors. Every rank is a direct output of the $/GB formula described above. This policy is non-negotiable and has been in place since PrepaidSIM launched.
The ranking algorithm has no input fields for payment, promotion, or provider preference. There is no mechanism to purchase visibility on any country page. A provider that offers a higher affiliate commission rate still appears below any cheaper competitor in every ranking table on the site.
PrepaidSIM does not accept sponsored content, paid articles, “partner spotlights,” or any other commercial placement. The only way to rank higher is to offer a cheaper plan per GB in the relevant market. Affiliate disclosure labels appear on every country page where commission links are present.
Methodology questions
Devices, tools, and speed protocol
PrepaidSIM tests eSIM activation flows and network performance on five devices spanning both major mobile platforms: iPhone 16 Pro running iOS 18, iPhone 15 Pro Max running iOS 18, Samsung Galaxy S25 Ultra running Android 15, Samsung Galaxy S24 Ultra running Android 15, and Google Pixel 9 Pro running Android 15. Testing across both iOS and Android matters because eSIM installation flows, QR code scanning behavior, and network switching behavior differ between platforms. Some providers handle one more reliably than the other, and we document those differences where they exist.
Speed measurements use the Ookla Speedtest app (Speedtest by Ookla). For each provider and destination, we run a minimum of ten speed tests distributed across three times of day: morning (08:00-10:00 local), afternoon (13:00-15:00 local), and evening (19:00-21:00 local). We discard the top and bottom ten percent of results to remove outlier readings caused by momentary congestion or interference. The remaining readings are averaged for the published figure. All speed tests use the nearest Ookla server with less than 50ms latency to isolate network performance from server distance. Speed data sources are cited as “Source: Ookla Speedtest Intelligence” on all country pages.
Activation flows are screenshot-documented at each step on both iOS and Android, providing a visual record of what a user sees. Activation time is measured from QR code scan (or the point of purchase in the provider app) to the first successful data request. We also run an airplane mode toggle test for each provider to measure reconnection time after disabling and re-enabling cellular, which affects real-world reliability in transit between network zones.
Price verification schedule
| Content type | Check frequency | Source |
|---|---|---|
| eSIM plan prices | Weekly (Monday 00:00 UTC) | Provider APIs and storefronts |
| Airport SIM kiosk prices | Monthly (top 35 airports) | Airport operator websites |
| Network speed data | Quarterly | Ookla Speedtest Intelligence |
| Exchange rates (USD normalization) | Daily | European Central Bank |
| Provider scoring | Weekly | Composite of all data sources |
Who runs PrepaidSIM?
PrepaidSIM is run by The Price Desk, a team of four analysts specializing in mobile connectivity, travel technology, and consumer pricing data. The team collectively holds over 15 years of experience in telecom pricing analysis and mobile network testing. The project started because finding an unbiased, up-to-date price comparison for travel data was harder than it should be.
The site is funded through affiliate commissions. Commissions keep the data free to access and the polling infrastructure running. They do not affect rankings.
What is the difference between eSIM and SIM card?
An eSIM is a digital SIM built into your phone. A physical SIM is a removable plastic card. eSIM activates instantly via QR code without visiting a store. Physical SIM requires a trip to a carrier store or airport kiosk. Both connect to the same mobile networks. Most phones made after 2020 support eSIM.