Apple talks a lot about privacy, but as soon as you start browsing in Safari your movements can be tracked by the websites you visit and your internet service provider, whether you're connected to Wi-Fi or using 3G, 4G or 5G.
Combining all this data, companies can know a lot about you, such as what you buy, where you shop, what you watch, when you go to bed and even if you're pregnant.
Using a VPN can keep all this information private, and it will also prevent anyone snooping on your browsing - or stealing personal information - when your iPhone is connected to public Wi-Fi.
It's important to note that using a VPN is usually against the terms and conditions of Netflix, BBC & Amazon.
While a VPN is new for many people, they are very simple apps to use and require no previous knowledge or technical expertise. It's as easy as launching the app, pressing the 'connect' button and then launching Safari or whichever other app you want to use.
Best iPhone VPN apps
NordVPN is our top pick, not just for iPhone, but Macs and other devices too.
It's a top all-round service, offering super-fast speeds thanks to its new 'NordLynx' protocol, lots of servers around the world and it's sensibly priced.
NordVPN is based in Panama, an ideal territory for privacy laws. But it doesn't collect or store any information about how or when you use the service, so it would have no data to hand over even if authorities were to request it, which they won't.
The service lets you connect to up to six devices at once, and has apps for iPhone and iPad, as well as Mac, Windows, Android and Amazon Fire TV.
If you subscribe for two years, you'll get a hefty discount which works out at £2.68 / $3.71 per month.
Read our NordVPN review.
ExpressVPN is another excellent choice for your iPhone. As with the others here, there are also apps for other popular devices, and you can use it on five of them at the same time, so it should cover the whole family.
The service bills itself as a premium choice and one way it differs from certain rivals is that all its servers are 'read-only' which means no data is ever stored on a hard drive. And that makes it even more secure from hacking.
It's based in the British Virgin Islands for privacy reasons and, like Nord and others here, doesn't store any data about your use of its service.
It unblocks Netflix and other streaming services, and offers fast connection speeds.
The best deal is the 15-month subscription, which works out at $6.67 (£5.19) per month and saves you 49% over the month-long option at $12.95 (£10.07).
Read our ExpressVPN review.
Sometimes you get what you pay for, but that adage can't be applied to VPN services. Surfshark is one of the cheapest options, yet there's so much to like.
It has a slick, simple interface which makes it easy to pick from one of the 1700 servers on offer in 63 countries. Those numbers are considerably higher than a year ago, and it's not just hardware that Surfshark is investing in.
The company has released new features on a regular basis, and is one of the only VPN services that offers two-factor authentication. It doesn't put any limits on the number of devices you can use simultaneously either.
Currently, the two-year subscription is the best deal at just £1.95/$2.49 per month. Take a look at the prices for all subscriptions on the Surfshark website.
Read our full Surfshark review.
CyberGhost for Mac
As one of the longest-running, best-known VPN services, CyberGhost is another solid choice. It's headquartered in Romania, which is outside the 14-eyes group of countries that share intelligence.
One of the great things about CyberGhost is its ease of use. It's particularly good for unblocking videos (it supports 35 streaming services at the time of writing) and offers great connection speeds.
There are more than 6,500 servers available to connect to over 90 different countries.
You can get CyberGhost for £2.15/$2.75 per month if you sign up for a year, which currently includes six free months on top.
Read our CyberGhost review.
VyprVPN is unusual in that it owns and operates all of its servers and network hardware. Most VPNs rent their servers, install their custom software and manage it remotely.
This is why VyprVPN is a great choice for privacy, and it also offers good speeds thanks to the recent introduction of WireGuard. It's also why there are fewer servers, but they're distributed among a large number of countries.
You can get 75% off the usual monthly price when you subscribe to VyprVPN's two-year plan. This at £2.50/$2.50 for five simultaneous connections.
Find out more in our VyprVPN review.
PureVPN is notable not because it offers more than 2,000 servers (a respectable figure, but by no means the largest) but because those servers cover a whopping 141 countries.
You're unlikely to need to pretend to be in most of them, but it could be a bonus if you do need to access something that's not in one of the commonly covered regions, or live in one of those countries and prefer a local server for the best speeds.
The iPhone app is simple and smart, and picks the best server based on your chosen activity.
To use it, you can try it out for seven days for just 99c (about 75p). If you like it, then subscriptions starting at $2.88 (around £2.25) per month for two years.
Read our PureVPN review.
Ivacy is as close to a free VPN as you can get with a paid-for service. And we don't mean it's no good: it's just unbelievably cheap.
Click the link above and you'll see a five-year subscription deal. While that length of time might put you off, the up-front cost is about the same as many of the two-year deals here. So you're paying the same money (or less), but getting access for five years. If that's not convenient, we don't know what is.
As well as apps for iPhone and iPad, there are lots of others and you can use up to five devices at the same time when connected to Ivacy's VPN service.
It doesn't have the largest number of servers and you're not going to get the absolute top speeds, but the appeal here is value: it's a great service with minor niggles that you can read about in our full Ivacy review.