Best prepaid SIM card for travelling to the UK: Tesco Mobile

Heading to the UK soon? A prepaid British SIM card lets you use your smartphone, tablet and 3G laptop England without clocking up a massive data roaming bill through Telstra, Optus or Vodafone.

One of the best deals is with Tesco Mobile, an offshoot of the British supermarket Tesco.

Tesco Mobile resells the O2 mobile network. You can check O2's mobile coverage online -- but be sure to click the "Mobile Internet" button to see 3G coverage, otherwise the map just shows O2's 2G coverage which has very sluggish internet speeds.

The deal

Tesco Mobile's prepaid SIM card cost £15 (A$23). That gives you 500MB of internet data plus 250 minutes of calls within the UK and 5000 texts.

If you think you'll need more call time or texts there are higher plans available, although they all come with the same 500MB of data.

If you order an iPhone SIM from Tesco, for another £2.50 (A$3.80) you can boost your internet data allowance to 1GB. Micro-SIMs for iPhone 4 and iPad are available.

For non-iPhone SIMs, upgrading to 1GB per month is a bit more expensive – you'll be up for £7.50 (A$11.50).

Because this is a pay-as-you-go SIM there's no ongoing commitment. Your initial £15 fee will keep the SIM card active for a month.

Calling back to Australia

Calls to Australian landlines or mobiles from the Tesco SIM card cost 25p (A$0.38) per minute -- so while using Skype would certainly be cheaper, a 10 minute call is still only going to cost you $3.80.

Obviously, these calls are not included in your 'calling minutes' that come with the SIM card. You'll need to buy some additional credit and load it on to the SIM card to make calls to Australia (see "topping up" below.)

Receiving calls from Australia

Your Tesco SIM card will have a UK +44 number, so it will be an international mobile call for people in Australia who want to reach you.

However, you can use our trick of diverting your Australian mobile through Skype to allow people to call you at no extra cost to them, and a fairly minimal cost to you.

Of course, given the Tesco SIM has a generous data allowance, you could also run the Skype app on your phone, and receive calls for free on that.

Skype for mobile is available for iPhone, most Nokia handsets, and Android phones (from companies like HTC, Samsung, LG, Motorola and others). More details are at the Skype on your mobile site.

Buying it

You can find a Tesco Mobile store using the Tesco Store Locator -- just enter the location you'll be visiting, select "phone shop" on the left, and click the "locate store" button.

Alternatively, the SIM card can be delivered free of charge to any address in the UK, so you can order it in advance of your arrival if you like and have it waiting at your accommodation.

We did noticed that when ordering online, the order process requires an 11 digit phone number. We put in our Australian mobile number with 61 at the beginning and an 0 at the end, and the site accepted it (e.g. 0421 123 456 becomes 614211234560).

Don't forget your phone will need to be unlocked. If you bought it on a plan from Telstra, Optus, Vodafone, 3 or one of the other Australian mobile resellers, chances are it will be locked to only use SIM cards from the original provider.

If you have had the phone for a while, most mobile networks will unlock the phone free of charge for you.

For tips on unlocking an iPhone bought in Australia, see our article, Top 5 tips for travelling with an iPhone.

Topping it up

If you run out of credit on the SIM, you can buy more by dialling 4444 from the handset, free of charge. You can then use a voucher purchased at one of 100,000 outlets in the UK, or pay by credit card over the phone.

There's a full list of topping-up methods here.

You can also top-up online at the Tesco Mobile website.

Setting up your phone to work with it

To get the internet working on your phone, you'll need to change the "Access Point Name" (APN) setting in it.

Tesco's APN details are:

APN: prepay.tesco-mobile.com
Username: tescowap
Password: password

To do this on an iPhone, connect the iPhone to a Wi-Fi hotspot, and in the iPhone's web browser, go to the website unlockit.co.nz. Select "custom APN", then from the drop-down list, select "UK - Tesco". Then click "create profile" and "install".

On an Android phone, we highly recommend the Tweakker app which costs A$4.16 to download and install on your phone, but will handle the settings for you automatically.

For instructions on how to change the settings manually on an iPhone, Android-based phone, Windows Phone 7 handset, or Nokia phone, go to unlockit.co.nz.

For other models of phone, google "How to change APN [your phone model]", e.g. How to change APN Sony Ericsson W705.

Note: if you change the SIM card in your BlackBerry, all internet services such as email, apps and web browsing will stop working. You'll only be able to make and receive calls. This is one of the limitations of BlackBerry handsets -- the internet side of it is tied to the Australian SIM card.

Cancelling it at the end of your trip

We did notice that it's an monthly auto-renewing SIM card so you will need to ring up Tesco and cancel it before the end of your trip. You can call 4455 from the handset for 20p (untimed) to get through to customer service.