Roaming bill shock on a work trip: the five real causes, and the setting that stops each one

Almost every large roaming bill comes from one of five things, and four of them are settings somebody forgot rather than prices somebody hid. A country the bundle did not cover, a network on a ship or an aircraft, a laptop tethered to the phone overnight, a pass that ran out in the middle of the trip, and a second line quietly left with data roaming on.

The scale is not a rumour. Ofcom modelled a week of typical mobile use for a UK customer and found it costing between nothing and £15.75 in the EU, against £47.95 to £215.55 for the same week in Saudi Arabia, depending on provider (Ofcom, Mobile roaming: strengthening customer protection, 22 March 2024, figure based on providers' websites accessed in February 2024).

Every price below is quoted from the carrier's own published rate card with its date. Rates differ by country, by contract, by whether the line is a business or a consumer one, and UK business prices are quoted excluding VAT while consumer prices include it. Treat them as illustrations of the order of magnitude, then check your own contract.

Cause 1: the country was outside the bundle zone

The single most common cause, and it is rarely dramatic at the point of sale. A plan says "roaming included" and the traveller reads that as "roaming included". The carrier means one zone.

EE Business puts it about as plainly as a carrier ever does: "No EE Business plan includes mobile data outside our Europe Zone as standard" (EE Business, roaming, no date shown on the page). EE's consumer price guide says the same from the other direction: "To use data whilst roaming abroad outside of the EU/EEA/Switzerland you will need to purchase a pass" (EE plan price guide, charges applicable from 31 March 2026).

O2 prices the same gap as a per megabyte rate for business customers: "data outside of our Europe Zone is charged at £6 per MB", excluding VAT (O2 Business, call and data costs while abroad, no date shown). Six pounds a megabyte is not a typo. One photograph sent from a taxi is several pounds.

Deutsche Telekom takes the opposite approach, and it is worth knowing because it is the design that makes bill shock impossible: in country groups 2 and 3, "ohne gebuchten Datenpass ist keine Datennutzung im Ausland in den Ländergruppen 2 und 3 möglich, so dass keine Kosten für Datennutzung anfallen können", which is to say no pass means no data, and therefore no charge (Telekom, Preisliste Mobilfunknutzung im Ausland, Stand 8 September 2026).

The setting that stops it: data roaming off on the company line, before departure, not on arrival.

• iPhone: "go to Cellular Data, then tap Cellular Data Options, and turn off Data Roaming" (Apple, About cellular data roaming options, 14 September 2026). Some regions label that first entry Mobile Data or Mobile Service.
• Pixel: Settings, Network and internet, SIMs, turn Roaming off (Google, Reduce and manage mobile data usage, no date shown; the page notes "some carriers charge extra for data roaming").
• Samsung: Settings, Connections, Mobile networks, Data Roaming (Samsung UK, last updated 5 June 2026).

With that switch off the line still receives calls and texts. It simply cannot spend. A travel data eSIM then carries the internet, and the two coexist without either interfering with the other.

Cause 2: the phone found a ship or an aircraft network

This is the one that produces the invoices people photograph and send round the office, and it is not covered by the protections most travellers assume they have.

The EU roaming regulation names the problem in its own recitals: services on board marine vessels and aircraft are "provided through types of radio networks other than terrestrial networks", charges for them "are significantly higher than tariffs for regulated roaming services", and roaming customers on them "are at greater risk of bill-shock" (Regulation (EU) 2022/612 of 6 April 2022, recital 46). The Commission states the consequence directly: services provided via satellite systems on board ships or aeroplanes "are not subject to the binding price caps of the Roam Like at Home regime" (European Commission, roaming questions and answers, last updated 28 July 2026).

What that costs, from three rate cards:

O2 handles it differently again. It lists AeroMobile, Maritime Communications Partner, OnAir, OnWaves and Thuraya inside its Zone 6, Rest of World, and says that on those networks "you can make calls or send texts but data won't be available" (O2 Business, no date shown). Three carriers, three completely different answers, which is exactly why a company cannot have one rule about this.

The setting that stops it: the same data roaming switch, kept off for the whole journey, not just the destination. A phone left on during a ferry crossing or a long taxi along a coast will attach to whatever it finds. Telekom adds a line worth remembering: "die Nutzung von Satellitennetzen ist nicht Gegenstand dieser Preisliste", meaning satellite use is not priced in the ordinary rate card at all.

Note that a travel eSIM does not rescue you here either. These networks are not ordinary roaming partners, and the correct move on a ship or a plane is the ship's or airline's own Wi-Fi, or nothing.

Cause 3: a laptop on the hotspot, syncing all night

The traveller does nothing wrong and the number still lands. A laptop connected to the phone's hotspot behaves like a laptop on office broadband: cloud storage catches up, the operating system downloads the update it has been waiting for, and a week of backlog moves in an hour. On a £6 per megabyte rate, a single system update is a four figure number.

This one is arithmetic rather than policy, and it is the reason the tethering guide exists: working from a laptop abroad has the realistic per hour figures and the list of what to switch off first. If you are estimating how much data to give somebody in the first place, how much data apps really use is the sizing.

The settings that stop it: mark the hotspot connection as metered on Windows, or turn on Low Data Mode for it on a Mac; pause cloud sync while tethered; turn off automatic system and app store updates; and download the documents before leaving. Five minutes of that does more than any plan size.

Cause 4: the pass ran out in the middle of the trip

Roaming passes are bought in units of time, and time ends. EE's rest of world passes come as 24 hour and 7 day passes, its EU passes as weekly and 12 day ones, and its business roam abroad pass runs 30 days (EE price guide, from 31 March 2026; EE Business out of bundle charges). On a ten day trip with a seven day pass, days eight, nine and ten are billed at whatever the standard rate is.

The trap is that the phone gives no sign. Data does not stop when the pass ends: on most contracts it keeps working, and the meter simply changes. The traveller notices nothing until the invoice.

What stops it: know the end date before you leave, put it in the calendar, and prefer a plan whose failure mode is stopping rather than charging. This is the honest argument for a prepaid travel data eSIM on a trip of uncertain length: when a data plan runs out it stops, and stopping is a problem you can solve from a café. It is also the reason Telekom's design above is safer than it looks, because no pass means no data rather than no limit.

Cause 5: the second line was left on data

A modern work phone often has two lines in it: the company line and something else, a personal line, an old carrier profile, a travel eSIM from a previous trip. Only one of them carries data at a time, but the wrong one can be the one carrying it.

Worth correcting a myth here, because it sends people to the wrong setting. Apple's dual SIM feature "Allow Cellular Data Switching" lets the phone move data between lines during a call, but Apple states that "this cellular-data switching won't work if you're currently using Data Roaming" (Apple, Using Dual SIM with an eSIM, 17 September 2026). So the thing to check is not the switching feature. It is data roaming, on each line separately.

The setting that stops it: on a dual SIM iPhone, Apple's instruction is to "turn on Cellular Data, tap the number you want to modify, then tap Cellular Data Options, and turn off Data Roaming", and the phrase that matters is the number you want to modify, because the setting is per line (Apple, 14 September 2026). Do it for every line in the phone, then set mobile data to the travel eSIM and leave the others alone.

Keeping the home line switched on but unable to spend is the whole trick, and it is also what keeps verification codes arriving: travel eSIMs and SMS codes covers that setup.

Does data roaming cost money, and who pays for it

Two separate questions that get answered as one.

Does it cost money depends entirely on where you are standing. Inside a zone the contract includes, roaming is usually free or a small daily fee: O2 states that "roaming in our Europe Zone is included in your tariff", while EE charges £2.72 a day in its EU zone on consumer plans (EE price guide, from 31 March 2026) and £2.38 a day on business ones (EE Business, no date shown). Outside that zone the same phone is on metered or blocked data, at the rates above.

Who pays is a contract question between the employee and the employer, not a telecoms one, and it is the part a travel policy should settle in writing before anyone leaves. On a company line the company pays by definition, because the bill arrives on the company account, which is precisely why the restrictions above matter. On a personal phone used for work, whether the company reimburses a phone allowance, a roaming pass or a travel data plan is a policy decision, and an unwritten one always becomes an argument after the fact.

That clause belongs in the travel policy alongside the ones about who books and who approves. Our guide to corporate travel policy and duty of care covers the shape of that document, and business eSIM explained covers which of the two very different products the phrase describes when a company goes shopping for one.

What protection actually still exists

Less than most people think, and different on each side of the Channel.

In the EU, the roaming regulation obliges providers to apply a default financial limit for data roaming, "close to, but not exceed, EUR 50 of outstanding charges per monthly billing period, excluding VAT", to notify at 80% of it, to notify again when it would otherwise be exceeded, to notify above EUR 100, and if the customer does not respond, to "immediately cease to provide and to charge" (Regulation (EU) 2022/612, Article 14(4)). The regulation entered into force on 1 July 2022 and expires on 30 June 2032.

The part almost nobody knows is Article 14(8): that protection follows the customer outside the Union and onto non-terrestrial networks too. And its exception is exactly where the bills come from, because the guarantee does not apply "if the visited network operator in the visited country outside the Union does not allow the roaming provider to monitor its customers' usage on a real-time basis". In that case the customer gets a free SMS on arrival saying the guarantee is not available, and that is all.

In the UK, the old £45 default data roaming limit is no longer a requirement. Ofcom is explicit: the retained roaming regulations "included the original sunset clause from the EU rules of 30 June 2022 which meant that these roaming rules fell away from July 2022", so "providers are not required to provide a default data roaming limit of £45 (excluding VAT) per month. However, many providers currently continue to offer this protection voluntarily" (Ofcom, 22 March 2024). EE Business, for instance, still applies a £45 cap on Business Connect data (EE Business roaming FAQs, no date shown), and O2 prints a £36 default business data cap. These are company policy, not law, and they differ.

What replaced the old rules, from 1 October 2024, is General Condition C3.15: a free notification when the device connects to a roaming network, saying whether roaming is included there, what it costs and that a billing limit can be set. The surviving statutory protection is the bill limit under section 124S of the Communications Act, and Ofcom notes the limitation that matters abroad: "if roaming in your destination is included in your contract, any bill limit will apply while you are abroad" (Ofcom, mobile bill limits, last updated 31 January 2025).

In its 2024 research Ofcom found that 71% of pay monthly customers were unaware the £45 default had ever existed, and that among the 49% who had set a bill limit the average was £4.08. A protection nobody knows about is not a protection.

The five settings, in one place

None of that requires a purchase, and it is the part a travel manager can put in an email today. If the answer for a particular set of destinations is a travel data plan, tell us where people are going and for how long, and we will say plainly whether it fits: support.

Sources: Ofcom, "Mobile roaming: strengthening customer protection", statement, 22 March 2024, including the figure on a week of typical usage based on providers' websites accessed February 2024; Ofcom, "Mobile bill limits", last updated 31 January 2025; Regulation (EU) 2022/612 of the European Parliament and of the Council of 6 April 2022 on roaming on public mobile communications networks within the Union (recast), OJ L 115, 13 April 2022, Articles 1(2), 14(4), 14(8) and 24 and recital 46; European Commission, "Roaming: questions and answers", last updated 28 July 2026; EE plan price guide, charges applicable from 31 March 2026; EE Business, roaming and out of bundle charges pages, with columns dated from 31 March 2026, page itself undated; O2 Business, "Call and data costs while abroad", no date shown; O2, "Using your phone abroad", last updated 30 July 2025; Telekom, "Preisliste Mobilfunknutzung im Ausland", Stand 8 September 2026; Apple, "About cellular data roaming options for your iPhone and iPad", 14 September 2026, and "Using Dual SIM with an eSIM", 17 September 2026; Google, "Reduce and manage mobile data usage", no date shown; Samsung UK, international data roaming, last updated 5 June 2026. Carrier rates change, in the UK typically each 31 March, and differ by country, by tariff and between business and consumer contracts; business figures are quoted excluding VAT and consumer figures including it. Checked 29 September 2026.

Quick answers

Does data roaming cost money?

It depends which zone you are in, not whether roaming is on. Inside the zone a contract covers, it is usually included or a small daily fee, for example O2 stating that roaming in its Europe Zone is included in the tariff and EE charging £2.72 a day in its EU zone. Outside that zone the same phone is metered: O2 Business publishes £6 per megabyte, and EE says no business plan includes data outside its Europe Zone at all.

Who pays for roaming charges on a work trip?

On a company line the company does, because the bill arrives on the company account, which is why the prevention settings matter more than the reimbursement rule. On a personal phone used for work it is whatever the travel policy says, and if the policy says nothing the argument happens after the trip. Settle it in writing: who pays, up to what, and what the traveller should buy before leaving.

Is there still a £45 roaming cap in the UK?

Not as a legal requirement. Ofcom states that the retained roaming regulations fell away from July 2022 and that providers are no longer required to apply a £45 default data roaming limit, though many continue to offer it voluntarily. What remains is the bill limit under section 124S of the Communications Act and, from October 2024, a required notification when your phone connects to a roaming network.