Best SIM-only offers December 2025: Plans for all budgets
Looking for a new phone contract? Maybe you need more data, or you’re out of contract and looking for a better deal, or you just want to save some money; then we will cover it here.
SIM plans are a great way to help with all of the above, and if you just didn’t know what they were, we can help with that, too.
Basically, they are plans to connect a mobile phone to the telephone network, without the additional cost of a mobile phone that is available in regular contracts.
These SIMs are perfect if you bought the phone outright, SIM-free, or are out of contract, and want a better deal on data, minutes, text, or just to save some money.
The programs offer great value as companies can even undercut offers from the big networks, as many run behind the big boys.
We’ve selected the deals below, all of which are available in a variety of easy-to-use categories, taking into account monthly costs and data allowances (the latter is especially important in this age of broadcasting, in which we live).
And, if you’re in the market for a new phone, from Apple to Samsung and beyond, we’ve got you covered, with our buying guides for the best smartphones, the best mid-range phones, and the best budget phones.
Unlimited data deals
100GB+ Data Deals
50-100GB Data Deals
10-50GB Data Deals
Under 10GB Data Deals
How to choose the best SIM
There are various factors to consider when considering a SIM-only plan:
Data: Using the phone for streaming, gaming, apps and browsing the web away from Wi-Fi can put a strain on your data allowance. You may need to look at your current usage, and see what you use or may need in the future when considering an upgrade. It’s always worth giving yourself a data cap that gives you some wiggle room in relation to your average usage, to ensure you don’t have to incur extra charges if you happen to have a particularly heavy data month.
Contracts: SIM deals usually have shorter service lengths than single phone plans, usually 12 months or 30 days, and these offer more flexibility. While there are 18-month and even 24-month options available, we recommend that you choose a shorter length so that you are not tied down for a longer period of time if you are not satisfied with your service.
Networks: Most cell phone networks today offer a good network connection, and it’s worth testing what works best in the most common areas where you can be with your cell phone. With that said, there are networks running behind the usual EE, O2, Vodafone and Three that offer a good service and at a lower price, such as Smarty and Voxi. Some networks also come with additional free services and rewards, including O2 Priority and Three Plus, so it’s worth doing a bit of a comparison to see what you can get for your money.
