Best Unlimited eSIMs for UK 2025 | Affordable Unlimited Data Options

Planning a trip to the UK in 2025? How good, and staying connected with unlimited data makes everything easier. In this article, I’ll cover the best unlimited eSIMs for UK travel, what “unlimited” really means, how much they cost, and where to buy one. For a broader comparison of all UK eSIM options, you can also check out our full guide here: Best eSIM for UK Travel.

Why Choose an Unlimited eSIM for UK Travel?

When you’re heading to the UK, an unlimited eSIM can be a bit of a lifesaver. The convenience of not having to think about how many gigabytes you’ve got left is hard to beat, especially if you’re the type who likes to stream music on the Tube or post travel updates on the go. It also saves you from those shock roaming bills that your home provider might sneak in if you forget to switch things off.

For me, the biggest appeal is the flexibility. You install it before you fly, land in London or Manchester, and you’re instantly connected. If your trip goes beyond the UK, it might be worth looking at our Europe eSIM instead. It’s a similar price, but it covers more than 30 countries, including the UK, which makes it perfect if you’re planning to hop across the Channel or explore more of Europe.

What Makes an eSIM Unlimited?

Here’s the thing about “unlimited” eSIMs – they’re not all built the same. 99% of providers include some sort of limit, usually hidden in the fine print. At ZenSim, our unlimited plans give you 3GB of full-speed data per day, then speeds slow down until midnight when it resets. That way, you know exactly what you’re getting and there are no surprises.

Other providers, like Holafly, prefer to tuck their limits behind something called a “fair use policy”. Personally, I’m not a fan of that approach. It means you don’t really know what the cap is until you’ve already hit it. Some will mention it on their site, but often it takes a couple of clicks to dig through their policy pages. Transparency matters when you’re planning a trip, and that’s why I always suggest reading the details before you buy.

Benefits for Tourists Visiting the UK

Unlimited data in the UK can make your trip so much smoother. Think about it – you can use Google Maps without worrying about draining your allowance, stream your favourite shows on the train between cities, or jump on FaceTime to call family back home without checking your usage first. It’s especially handy if you’re travelling with friends and hotspotting to share your connection.

On that note, some providers do have hotspotting limits (or prevent it completely) so also watch out for that. We, of course have unlimited hotspotting at ZenSIm and we know of some competitors (hello Holafly) who limit you to 500MB so as always read the fine print (or one of our comparison articles haha).

Best Unlimited eSIMs for UK in 2025

There are quite a few providers offering unlimited data eSIMs for the UK, and while they all market “unlimited”, the details can be very different. Here’s a breakdown of some of the most popular options, how they compare, and what you should know before picking one.

ZenSim Unlimited

ZenSim offers two unlimited options for the UK: a 30-day plan for A$69 ($45 USD) and a 10-day plan for A$45 ($29 USD). Our unlimited plans give you 3GB per day at full speed, then speeds are reduced until midnight when it resets. What you see is what you get – no hidden policies buried three clicks deep. You also get unlimited hotspotting, which is handy if you need to share data with a laptop or travel buddy. On top of that, we’re an Australian-based company with a 4.9-star rating for customer service, which means you can actually get a quick response if you ever need help.

Holafly

Holafly is one of the better-known eSIM brands and they’ve built their reputation on offering unlimited plans where you can pick exactly how many days you need. Their 30-day unlimited plan costs A$117 ($74.90 USD) and their 10-day option is A$57 ($36.90 USD). The catch is that their “fair use policy” isn’t very clear – people online, including Reddit users, have tried to guess the actual data allowance but there’s no straight answer. They also limit hotspot usage to just 500MB a day, which can be frustrating if you rely on tethering.

Airalo

Airalo is probably the most recognisable name in the eSIM space. For the UK, though, their unlimited options are a bit limited. They don’t offer a 30-day unlimited plan but do have a 10-day unlimited plan priced at A$45 ($29 USD). While Airalo is convenient and has a big brand presence, their online reviews have slipped below 4 out of 5 stars, which shows not everyone is happy with the experience.

Simify

Simify is popular among Australians heading to the UK, and it’s always nice to support another Aussie company. Their unlimited options include a 30-day plan for A$99 ($59 USD) and a shorter 7-day plan for A$44 ($27 USD). The main downside is that they don’t have an app, which makes topping up or checking usage clunky compared to providers that give you a dashboard.

Saily

Saily is a newer name in the eSIM market, created by the team behind NordVPN. Their unlimited plans include a 30-day option for A$115 ($71.99 USD) and a 10-day option for A$56 ($34.99 USD). One thing they add is some extra security features, thanks to their VPN background, which could be appealing if online privacy is high on your priority list. Their pricing sits toward the higher end, but some travellers might find the added security perks worth the extra cost.

Where to Buy an Unlimited eSIM in the UK

If you’re wondering where to buy an unlimited eSIM in the UK, you’ve basically got two main choices – get it sorted before you fly or pick one up after you land. Both work, but there are some clear advantages to planning ahead.

Buying Online Before You Travel

These days, the easiest way to get an unlimited eSIM for the UK is to buy directly from a provider’s website before you even pack your bags. It’s honestly a game changer compared to the old days when you had to queue in a shop, cross your fingers, and hope you weren’t being stitched up on pricing (as we’d say back home in Australia). Now you can sit on your couch, compare providers side by side, check reviews, and pick the plan that suits your trip. The best part is that setup usually only takes a couple of minutes over WiFi, so you’re ready to hit the ground running the moment you land at Heathrow.

Purchasing eSIMs After Arrival in the UK

It’s still possible to buy an unlimited eSIM once you’re in the UK, online you’re your favourite provider (like us ;)) or from local providers such as at airport kiosks. The downside is that it can be more hassle than it’s worth buying in person. Local carriers often ask for ID or proof of address, and if you don’t speak the lingo of UK mobile plans, you might find yourself signing up for something that isn’t as unlimited as it looks. For most travellers, buying online is the smoother, less stressful option whether that is before or after you fly is up to you.

Best Unlimited eSIM for Short UK Trips

If you’re only in the UK for a week or so, picking the best unlimited eSIM for short UK trips is all about balancing convenience and cost. Unlimited plans give peace of mind, but sometimes a large data bundle can do the job just as well for less. For a bigger breakdown of UK eSIM options (not just unlimited), you can check out our main guide here: Best eSIM for UK Travel.

Plans Designed for 7–10 Days

Several providers now offer unlimited options specifically designed for shorter trips. At ZenSim, you can grab a 10-day unlimited plan for A$45 ($29 USD), which is perfect for a quick holiday or business trip. Holafly also sells a 10-day plan for A$57 ($36.90 USD), though keep in mind their hotspot is capped and their “fair use policy” isn’t clear on data limits. Saily comes in at A$56 ($34.99 USD) for 10 days, while Airalo has a A$45 ($29 USD) 10-day unlimited option but doesn’t offer longer unlimited stays. If you’re only in the UK for a week, these short-term plans can be a hassle-free way to stay online without overpaying.

When a Big Data Bundle Might Be Enough

If you’re a light to moderate user, a 10–20GB plan might be more than enough for a week in the UK. Using offline maps, connecting to hotel WiFi, and saving streaming for downtime can stretch your data further than you’d expect. Sometimes it’s cheaper and simpler than paying for an unlimited plan you won’t fully use. For instance, a 10GB plan can easily cover a week’s worth of maps, messaging, and social posts without breaking a sweat. If you’re interested in this route, check out our UK plans – they include both unlimited and big data bundle options so you can choose what makes the most sense for your trip.

How Affordable Are Unlimited eSIMs for the UK?

When people ask about the most affordable unlimited eSIM for UK travel, the good news is there are plenty of options. Pricing varies depending on how long you’re staying and which provider you go with, but generally you’ll find 10-day unlimited plans starting around A$45 ($29 USD) and 30-day plans ranging from A$69 ($45 USD) up to about A$117 ($75 USD). The trick is knowing when you actually need unlimited and when a capped plan could give you the same experience for less. If you’d like to see all the different UK options side by side, you can check out our main comparison here: Best eSIM for UK Travel.

Unlimited vs High Data Plans

Unlimited sounds like the obvious winner, but the truth is you don’t always need it. If you’re a heavy streamer, hotspotting daily, or uploading large amounts of content, then unlimited makes sense. But if your usage is more about maps, messaging, and the occasional TikTok upload, a 10–20GB plan might cover you just fine. For short trips especially, capped plans can be more affordable and still give you plenty of breathing room. At ZenSim, for example, you’ll find both unlimited and capped bundles so you can choose what fits your style of travel.

Getting the Most Out of Your UK eSIM

One of the features I like most about ZenSim is how flexible our eSIMs are. You can top up whenever you need, so you’re never stuck if your trip runs longer or you burn through your allowance faster than expected. We also let you add multiple countries to the same eSIM, which comes in handy if your trip involves stopovers in places like Dubai or Singapore. Instead of juggling multiple eSIMs, you keep everything on one profile and simply top up for the regions you’re passing through. And if your travels take you into Europe, our Europe eSIM plans will keep you connected across borders (including the UK) all on the same eSIM!

Frequently Asked Questions About Unlimited eSIMs in the UK

Here are some of the most common questions travellers ask when looking for the best unlimited eSIM for UK trips. Hopefully this clears up any confusion before you book your plan.

What’s the best unlimited eSIM for UK travel?

It depends on what you value most. If you want transparency, unlimited hotspotting, and responsive support, I’d suggest ZenSim. If you prefer bigger brand names, Holafly or Airalo might catch your eye, though both have drawbacks – like unclear fair use policies or fewer unlimited options. For a broader comparison, check out our UK eSIM guide.

Is unlimited really unlimited with eSIM providers?

Not exactly. Most providers set daily usage caps or throttle speeds once you hit a certain amount. At ZenSim, our unlimited UK plan gives you 3GB of full-speed data per day before speeds are slowed, and that cap resets at midnight. Other providers, like Holafly, tuck their limits away in “fair use policies” that aren’t always clear. So yes, unlimited is real – but it’s worth reading the fine print.

Can tourists get unlimited eSIMs in the UK?

Yes, absolutely. Unlike physical SIMs that sometimes require ID or proof of address, travel eSIMs can be purchased online and activated as soon as you land. You don’t need to be a UK resident to buy one, and the process is much simpler if you set it up before you leave home. Keep in mind most do not come with phone numbers if you did require traditional calling.

How much does an unlimited eSIM for the UK cost?

Pricing depends on the provider and how long you’re staying. For short trips, 7–10 day unlimited plans start around A$44–A$57 ($27–$36 USD). For longer stays, 30-day unlimited plans range from about A$69 ($45 USD) with ZenSim to A$117 ($75 USD) with higher-priced providers like Holafly. The key is to weigh the cost against how much data you’ll realistically use.

Do unlimited eSIMs include calls and texts, or just data?

Most unlimited eSIMs for the UK are data-only. That means no UK phone number for calls or SMS. But with apps like WhatsApp, FaceTime, or Messenger, you can still call and message freely over data. For most travellers, that’s more than enough. If you do need a local number, you’d have to look at a physical SIM or a more specialised plan from a local carrier.

Wrapping Up: Unlimited eSIMs for UK Travel

Unlimited eSIMs take the stress out of staying connected in the UK – no roaming fees, no SIM card hunts, just simple and flexible data for your trip. If you’re unsure which plan is right for you, or have any questions at all, feel free to reach out to us at ZenSim – we’re always happy to help. You can also explore our latest UK unlimited eSIM plans to get started today.