Sim Local Voucher ESIMDISCOUNT10 is a 10% discount code you type into the promotional field at the Sim Local online checkout, which brings your order total down to 90% of the listed price. That is the whole offer. There is no stored balance, nothing to print, and no credit left over afterwards. The question worth spending a few minutes on is not how it works but whether it changes anything for you — and the answer depends almost entirely on what you were going to buy and where you were going to buy it.

A flat percentage sounds the same on every order, but it does not feel the same. On the global eSIM plans listed in US dollars at the research date, 10% off produced savings at both ends of the scale. The smallest global plan, 3GB covering 109 countries for 31 days, was $10.50, so the code takes it to $9.45 — a saving of $1.05. The largest, 100GB across 116 countries for 31 days, was $93.50, so the code takes it to $84.15 — a saving of roughly $9.35. Between those sit the 50GB plan at $70.25 (about $63.23 after the code), the 30GB plan at $47.00 ($42.30), the 20GB plan at $35.00 ($31.50) and the 12GB plan at $20.00 ($18.00). Those were the prices on the research date and should be read as indicative rather than fixed.

Laid out like that, the honest summary is that this is a small discount in cash terms. If your trip needs a few gigabytes, the voucher saves you about the price of a coffee. If you are buying the biggest bundle for a long multi-country trip, it returns most of a ten-dollar note. Neither figure changes a travel budget. Both are free to collect.

The clearest winners are people who had already decided to buy a Sim Local eSIM through the website. For them the code is pure upside: the same plan, the same activation, ten per cent less money. Nothing about the purchase has to change to earn it.

Beyond that, a few groups get slightly more out of it than others:

If you intend to buy at an airport, the voucher is of no use to you. Sim Local is a physical retailer as well as an online one, selling through airport stores, kiosks and vending machines — its own site names locations including Dublin, London Heathrow, London Gatwick, Brussels, Athens, Madrid and Copenhagen, plus US airport partnerships, and a UK airport distribution partnership with WHSmith Travel dating from 2017. None of those tills has a box to type ESIMDISCOUNT10 into. A code that only exists at an online checkout cannot follow you to a counter.

The workaround is easy enough — an eSIM needs no physical handover, so ordering online loses you nothing except the walk-up convenience. But it does move your decision earlier. You place the order, apply the code, and receive the activation instructions by email or through the app rather than buying on impulse at the gate. It is also not documented whether the code functions inside the iOS and Android apps or only on the website, so if the app shows no code field, the website is the safer route.

The second group who should not bother are people using the discount as a tie-breaker between providers. Ten per cent on a modestly priced eSIM is not a large enough margin to override a coverage gap or a missing feature. If a plan does not cover the country you are visiting, the code cannot fix that.

A discount reduces a price; it does not improve a product. That matters here because of one quirk in the plan list worth noticing regardless of any voucher: the number of countries covered does not rise with the data allowance. The 50GB plan listed 117 countries while the 30GB plan listed 71, and the smallest 3GB plan listed 109. Buying more data does not automatically buy wider coverage, so the destination list on the exact plan you are considering is the thing to check, not the headline figure on a bigger one.

Similarly, whether a plan includes calls and SMS or is data-only varies. Calls and texts are described as available "in popular destinations", which makes voice a per-plan detail to confirm rather than something to assume. Network speed is 4G, 5G or 3G depending on the plan and the local network. Applying the code has no bearing on any of it.

The realistic comparison is not "with voucher versus with a better voucher" but "with voucher versus full price". Buying without the code gets you exactly the same eSIM at 100% of the listed price. There is no bundled extra, no loyalty credit and no trade-off in return for skipping it. That makes the decision one-sided: if the field accepts the string, take it.

The reasons to buy from Sim Local in the first place sit elsewhere. The company was founded in 2011 by Irish entrepreneur Killian Whelan, is headquartered in Dublin with a London office, and a third-party profile puts it at roughly 73 employees across three continents as of February 2026, with 4 million customers since 2011. It sells plans from operators including EE, Orange, Lycamobile, Three, AU (Japan), True, Digicel and Mobifone. It advertises coverage of more than 150 countries and regions, activation within minutes with no SIM to swap, and up to 10GB of full-speed data daily without throttling — the last being the company's own claim and a cap on full-speed data rather than an unlimited promise. It also advertises a "No Quibble Refunds" guarantee, whose conditions are worth reading on the policy page before you lean on them. Those are the things that should decide the purchase. The voucher is a finishing touch.

Several things about ESIMDISCOUNT10 are not documented, and pretending otherwise would not help. It is not stated whether the code covers every plan — local and regional plans as well as global ones, or physical SIMs bought online. It is not stated whether there is a minimum spend, an expiry date, a per-customer limit or a first-order-only restriction. The exact position of the code field on the checkout is not documented either; at most stores it sits near the payment step, sometimes tucked behind a small link you have to expand.

None of that makes the code doubtful. It means the order total is your evidence. Enter the string exactly as written, with no spaces, then look at the figure. If it has fallen to 90% of what it was, the code has landed. If it has not moved, it has not been accepted, and paying anyway will not apply it afterwards.

Treat this as a small, real improvement to a decision you were already making rather than a reason to make the decision. The saving is a couple of dollars at the bottom of the global range and close to ten at the top. It costs nothing to attempt and it either applies or it does not. Check the country list on the specific plan you want, confirm whether that plan includes voice if you need it, buy online rather than at a kiosk, and verify the total before you pay.

Promotional terms, eligibility and values are set by the provider and can change at any time. Always confirm the current terms on the official site before signing up or completing a purchase.