giffgaff is a UK mobile service provider which has been a Which? Recommended Provider for several years running. giffgaff is an MVNO which uses the O2 cellular network and supports LTE data speeds (often referred to as "4G" data). I've been using giffgaff since last year and I'm very happy with the service.
There are no running contracts, but you have the option of either using giffgaff as a pay-as-you-go service, or purchasing a bundle known as a goodybag which lasts for one month and includes a certain allowance of data, text messages, and calling minutes.
giffgaff tariffs are all SIM-only, so you'll need to have a mobile device which is unlocked (or is locked to the O2 network) in order to use a giffgaff SIM card. giffgaff do also sell mobile devices, but I have no experience with buying handsets from giffgaff so this review will talk only about giffgaff as a mobile service provider.
By default a giffgaff SIM simply operates on a pay-as-you-go basis. The current [July 2018] data cost of 5p/MB and text cost of 5p/message are not the lowest pay-as-you-go rates you can find, and at 15p/minute the cost of making calls is relatively high. So if you're a pay-as-you-go user then you might find cheaper tariffs elsewhere. But for anything more than light usage, it's recommended to purchase a giffgaff goodybag (see below). Also note that each time you top-up your credit balance, or purchase a goodybag, you unlock free giffgaff-to-giffgaff calls and texts for the next three months, so having friends on the giffgaff network will reduce costs.
On giffgaff you can never incur any costs beyond the amount of credit you have remaining, so you can't run up a debt and will never receive an outstanding bill. However, by default auto top-up may be enabled on your giffgaff account, and this means that when your credit balance falls below a certain amount then your card will be automatically charged to purchase an additional credit top-up. If you need to be in control of when money leaves your bank account, then you should disable auto top-up, otherwise you can be taken by surprise. (Auto top-up also becomes quickly expensive if you accidentally start using credit for heavy data usage.)
If you're going to send more than a hundred texts each month, or make more than a half-hour of calls, or use more than a 100MB of data, or a lesser mix of all three, then you'll find it cheaper to purchase a goodybag. A goodybag is a bundle of data, text, and call allowances (to standard UK personal numbers). You can have one goodybag active at a time, and once purchased for a fixed price its allowances last for up to one calendar month. As of 11th July 2018 the current selection of goodybags you can choose from looks like this:
|Allowances for the month|
|Price per month||Data||Call minutes||Text messages|
Once a whole calendar month passes, any unused goodybag allowances are lost. If an allowance, such as data, is used up during the calendar month then any additional usage will be taken from your pay-as-you-go credit balance. If you have no goodybag allowance remaining, and no credit, then you simply won't be able to use that feature until you buy another goodybag or purchase a credit top-up.
For convenience, you can have a recurring goodybag enabled so that when one goodybag expires after a whole calendar month, giffgaff automatically charge your card to purchase another goodybag of the same type to cover you for the next month. But this is optional, and you can disable recurring goodybag purchase if you want to be in control of when and which goodybag.
This is a frequent question, but the fact is that giffgaff do not offer any goodybag which offers unlimited data. The £25 "Always On" goodybag includes a 20GB data allowance (and unlimited standard UK calls and texts), and once you exceed the 20GB data allowance, you will continue to be allowed to use data without charge, but at a slower speed. The idea is to make sure you still have data access without incurring extra charges if you accidentally exceed your allowance some months. But this is not unlimited, and users who greatly exceed the 20GB limit will be warned to ease off, and continued excess will lead to giffgaff refusing to sell such a user the "Always On" goodybag in future.
That said, giffgaff do allow data tethering. But for heavy usage (such as high-definition video streaming, bulky file sharing, etc) it is strongly recommended that you get a proper home broadband connection, as no mobile provider is prepared to handle such sustained high data volumes.
I often provide help on the giffgaff community forums, and certain questions come up time and again, so here is a list of important information you should known before you consider giffgaff as your mobile service provider.
If you're thinking about giving giffgaff a try, then order a free SIM using my affiliate link and you'll get a bonus of £5 credit if you activate the SIM (which requires a minimum initial credit top-up of £10). There is no minimum contract, so if you don't find giffgaff suits you then you won't be tied to them. And you can easily transfer your existing mobile number to giffgaff, or away from giffgaff, so changing provider doesn't mean that your contacts will lose touch with you.