Guide to pay-as-you-go mobile broadband and how to top up

With mobile broadband pay as you go tariffs (often shortened to PAYG mobile internet) you are charged a set rate for each GB of data you download, or for a specific period of time spent online (such as per day). Mobile internet PAYG deals are generally similar to the mobile phone deals of the same name, so if you've had a PAYG handset you'll be on familiar ground.

Pay as you go mobile broadband deals are pretty flexible, and so would be good for people who don't download that much, or who are irregular internet users. PAYG mobile internet is also an excellent option for those who don't want to commit themselves to lengthy subscription.

To get up and running with PAYG mobile internet, you'll first need a new SIM card (you can't use a mobile phone one). For most people this will come with a mobile broadband dongle, but they are sometimes supplied with mobile broadband modems inside laptops. Once you have this you can 'top-up' your account with credit as and when you need it.

How to top up mobile broadband

When you're close to using up your initial PAYG mobile internet credit, you'll need to top-up before you can keep surfing. The SIM card you insert into your dongle or laptop comes with its own mobile broadband number; it's a good idea to jot this number down somewhere safe so you have access to it, even when you're on the move. The easiest way to do this might be to add it as a 'My Mobile Broadband' number on your mobile phone.

Gone are the days when you had to trudge around looking for an open newsagents that sold top-up cards before you could get back up to speed – there is now a far more convenient way to get a mobile broadband top-up. All the PAYG mobile broadband providers have an area online where you can add more credit simply by using a secure username and password. The good thing is that you can always access this via your dongle even when you are out of credit, so it doesn't matter if you run out of data in the middle of nowhere - see below for details of your specific ISP.

For some services you can still buy a voucher from your provider’s high street store, or look out for the 'top-up' logo in the windows of retail outlets like supermarkets, newsagents and off licences. Using an E Top-Up card given to you by your provider, you can add credit by passing this card over to the vendor.

O2 mobile broadband
O2 does not allow broadband top-ups using the normal methods such as E Top-Up or vouchers from an O2 store, you can only top-up by logging in to its mobile broadband area and purchasing with a credit or debit card. This can be accessed to check and top-up your credit even when your mobile broadband credit has expired or run out.

Vodafone mobile broadband
Vodafone users can top up by purchasing a PAYG voucher and these are available in a variety of increments. The number on the voucher can be entered via the Vodafone software on your desktop, if this doesn't work you can call customer services who can apply the voucher for you. Alternatively, you can pay with credit or debit card through the account page at the Vodafone web site.

3 mobile broadband
3 mobile broadband can be topped up just the same as their mobile phones, by purchasing a voucher in shops or paying online with a credit or debit card. After this you must then follow the instructions online to convert this credit to an Internet Add-On so it can be used for mobile broadband.

T-Mobile mobile broadband
T-Mobile users can top up with vouchers purchased in stores. Text "VO [voucher number]" to 150 to apply the top-up. You can also top-up with a credit/debit card via T-mobile online.

If you want to avoid messing around with mobile broadband top-ups for a little longer when buying your dongle, look out for mobile broadband starter kits. These come ready loaded with extra data allowance – anywhere from three months to a year on T-Mobile, or 3GB to 12GB with 3 Mobile Broadband (to be used within a three-month period).

Does my top-up credit expire?

Most providers specify your credit must be used within a set limit (often 30 days), otherwise it expires and is no longer available, so if you put £20 on and come back months later you'll have to spend more money to get online.