Planning a trip abroad with a family in tow is complicated enough without your phone bill coming home looking like it needs its own mortgage. I’m heading to the US in a few days, and while I’ve got roaming sorted through O2, I’ve learned over the years that “sorted” and “fast” are two very different things. If you’ve ever stood in a foreign city trying to load Google Maps at the speed of a 1990s dial-up modem, you’ll know exactly what I mean.
The problem is that UK carriers have done a reasonable job of making roaming sound simple, but the fine print is where it gets you. Speed caps, data limits, daily charges. It adds up fast. And if you’re travelling with teenagers who think a 4K YouTube video at the airport is a basic human right, you need to understand what you’re actually paying for before you board.
What to actually look for before you travel
Speed caps: the silent performance killer
This is the one that catches most people out. O2’s roaming in the USA, whether you’re on a bolt-on or an inclusive plan, caps data speeds at 2 Mbps. That sounds fine until you realise it’s barely enough for standard-definition video on a small screen. HD video calls? Forget it. Downloading a large navigation map in a hurry? Good luck. Three’s Go Roam Around the World covers the USA too, but even on a 5G plan, you’ll typically land on 4G speeds when roaming. The networks are honest about this if you dig into the terms, but they’re not exactly putting it on a billboard.
Daily limits vs total allowance
This is the detail that tripped me up early on with travel eSIMs. An “unlimited” plan with a 1GB daily cap is not the same thing as a 5GB plan. If you need 3GB on a big sightseeing day, a 1GB daily cap will leave you throttled and frustrated for the rest of the afternoon. Work out how you actually use data day to day before you buy. A 5GB fixed plan at a lower price may serve you far better than an “unlimited” plan where the daily ceiling hits your workflow hard.
Hotspot and tethering support
If you’re planning to use your phone as a hotspot for a laptop or a kid’s tablet, check this before you buy anything. Three restricts tethering on its roaming allowance on some plans. Many travel eSIM providers also exclude hotspot functionality entirely, or count tethered data separately. It’s the kind of thing you only discover when you’re sitting in a hotel room trying to work.
Keeping your UK number active
Here’s the clever bit that makes travel eSIMs genuinely useful rather than just a workaround. Most modern phones support dual SIM, and an eSIM sits alongside your physical UK SIM. That means you can use the eSIM for fast local data while your UK number stays live for calls and texts. WhatsApp, iMessage and similar apps will run over the eSIM data. Standard calls and SMS from your UK number still work as normal. It’s the best of both worlds, and it’s exactly the approach I use every time.
My eSIM picks for the USA
Uswitch eSIM
This is the one I used for my last Vegas trip and the one I’ll be using again. It’s straightforward to buy, activates cleanly via QR code, and the coverage has been solid. I’ve had no drama getting it set up, and in Las Vegas the speeds were noticeably better than my O2 connection. The process is simple: scan the QR code in Settings, label the plan something obvious like “Travel USA”, complete the install, and when you land, turn off your primary line and switch on the eSIM with data roaming enabled.
Pro: Familiar UK-friendly interface, good USA coverage, worked well in Las Vegas
Con: Check the daily cap carefully before buying, as “unlimited” options vary
SimCorner
I’ve also used this for a Vegas trip and it delivered. SimCorner has a clear website, the QR code activation is the same as any other eSIM, and their USA plans are well priced. Worth comparing against Uswitch on total allowance and daily limits for the dates you’re travelling.
Pro: Competitive pricing, reliable activation process
Con: Plan options can change frequently, so always verify current offers before buying
GlobaleSIM
I’ve used GlobaleSIM for South Africa, which performed well in a market that can be tricky for coverage. Their USA plans are also available and worth considering, especially if you’re after a multi-country option or travelling beyond the US on the same trip.
Pro: Good for multi-destination trips, worked well in South Africa
Con: Check hotspot availability on whichever plan you choose, as it varies
Airalo
One of the most widely known eSIM marketplaces globally and worth having on your radar. Airalo lets you compare providers and buy directly in-app, which is convenient if you’ve left it late. USA options are plentiful, including regional and nationwide plans.
Pro: Large selection, easy app, good for last-minute purchases
Con: Quality varies between the underlying providers listed, so read reviews for specific plans
Holafly
Popular with UK and European travellers heading to the US. Holafly tends to market unlimited plans, but this is exactly where my earlier warning applies. Verify the daily high-speed cap before committing. Their customer support is generally responsive if you hit a problem.
Pro: Simple unlimited-style plans, easy to purchase
Con: Daily speed caps apply, and the fine print matters more than the headline
Quick comparison table
| Provider | Price (GBP, approx.) | Best For | Verdict |
|---|---|---|---|
| Uswitch eSIM | £15–£25 for 5–10 days | Tried-and-tested USA travel | My current pick for Vegas |
| SimCorner | £12–£22 for 5–10 days | Value-focused USA trips | Solid, reliable, worth comparing |
| GlobaleSIM | £14–£28 for 5–10 days | Multi-destination trips | Strong for Africa and USA combos |
| Airalo | £10–£30 depending on plan | Last-minute buyers | Huge choice but verify provider quality |
| Holafly | £20–£35 for unlimited-style | Users who want one plan, no counting | Read the daily cap terms carefully |
Pricing is approximate and subject to change. Always verify current plans before purchase.
Bottom line
If you’re on a budget and only need the basics, your O2 or Three roaming will get you online without extra kit. Just accept the 2 Mbps cap and plan around it. For a short city break where you’re mostly on hotel Wi-Fi, that’s probably fine.
If you’re a regular traveller, a remote worker, or someone who uses their phone heavily for navigation, video calls, and keeping the family entertained, get a travel eSIM. Buy it before you fly, install it at home, and activate it when you land. The activation process is the same across every provider: go to Settings, then Cellular on iPhone or SIM Card Manager on Android, scan the QR code, label it something sensible, and switch it on when you arrive. Turn your primary line off, switch on the eSIM, make sure data roaming is enabled, and you’re done.
The golden rule: never take “unlimited” at face value. A 1GB daily cap dressed up as unlimited is not what most people expect. Know your total allowance, know your daily ceiling, and check whether hotspot is included if you need it.
For families travelling to the USA, my current recommendation is Uswitch. Clear pricing, good coverage, and it’s held up through multiple trips for me now. SimCorner is a close second if Uswitch’s current plans don’t suit your dates.
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