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Best SIM only deals 2023: Scoop up OUTSTANDING offers from the top UK mobile networks this December

We've rounded up the best SIM only deals this month from all of the UK's mobile networks to save you big money

Searching for the best SIM-only deals can be a confusing process because each mobile network promises a range of data limits and extra goodies. But fret not, we’re here to help.

To help you find the best SIM only deal for your needs, we’ve rounded up the four best into categories below: the best overall, the best with unlimited data, the best budget option and the best deal if you have a need for speed.

This isn’t an exhaustive list, but rather a quartet of offers that the experienced SIM sommeliers at Expert Reviews are happy to recommend after calculating their overall costs and weighing them up against the competition. Beneath each deal, you’ll also find a table containing the key details to make your life easier.

FEATURED DEAL: Save a MASSIVE data boost from Smarty

As a winter warmer, Smarty is currently offering 125GB of data for just £12/mth on a rolling, one-month plan. That’s up from the usual 100GB you’d get for the same amount of money. That’s outstanding value from an award-winning mobile network.

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Which mobile network should you go for?

Now that you’ve perused our list of the best SIM-only deals, which mobile network should you sign up with? To help you find the best fit for your needs, we’ve rounded up three of our favourites below to help you decide.

1. Voxi

Voxi is our current favourite mobile network, offering a blend of affordable plans and engaging features. Although slightly pricier than some competitors like Smarty or iD Mobile, and with charges for EU roaming, its strengths lie in excellent data deals and unique unlimited streaming and social media capabilities.

The network’s plans are straightforward and commitment-free, often featuring double or triple data deals, along with unlimited social media and video streaming via a host of apps. These deals, despite not being the cheapest, are highly valued by customers, with nearly 97% being satisfied in our annual Mobile Network Awards survey.

Customer service at Voxi is above average, with over 62% of respondents being satisfied, though it hasn’t won specific awards in this area. The network runs on Vodafone’s infrastructure, ensuring reliable coverage and decent speeds, currently the third-fastest in the UK. Users report high satisfaction with signal strength and internet speeds, with Voxi winning an award for reliability.

Roaming services are an area for improvement, as Voxi requires the purchase of European or Global Roaming Passes, with no free roaming options available. Additionally, Voxi limits its extras to unlimited streaming and social media, without features like spending caps or early allowance refreshes.

Voxi balances its slightly higher price point with value-adding features, such as impressive data offers and unlimited streaming, making it a strong contender in the no-frills network category. Its satisfactory customer service, reliable coverage and speeds further enhance its appeal. Although not the cheapest or fastest, Voxi’s combination of affordability and unique features, alongside high customer satisfaction, earned it multiple awards, including the Best Mobile Network​​.

Read our full Voxi review

2. Smarty

Smarty, despite not repeating its previous year’s success in the Expert Reviews Best Mobile Network Awards, still stands out with excellent customer feedback, making it a great no-frills network. It offers great value with cheap data deals, impressive 5G performance and free EU roaming, although its customer service scores have dropped since last year and its data plans are somewhat confusing.

The network primarily offers SIM-only plans on a 30-day rolling contract, with voice and data-only options ranging from £6/mth for a 5GB plan to £20/mth for unlimited data. Notable features include Data Discount plans for unused data and Unlimited Data Passes for temporary data needs.

Over 95% of users were satisfied with the network’s value for money in our annual survey. While customer service scores have dipped, Smarty still performs better than many major networks. Coverage and speed are strong suits, backed by Three’s network, with substantial improvements, especially in 5G services, leading to high user satisfaction and an award in the Best 5G category.

Roaming includes free EU roaming up to a 12GB limit, with additional data add-ons available for further usage. Outside the EU, extra charges apply.

Smarty’s extra features are limited, with no spending caps or eSIMs but it does offer Wi-Fi calling. Overall, Smarty presents a compelling no-frills option, offering significant data for the cost, making it a favourable choice for customers looking for value without the constraints of an expensive, inflexible contract​.

Read our full Smarty review

3. iD Mobile

iD Mobile, straddling traditional and no-frills virtual networks, offers competitive SIM-only deals and diverse smartphone choices. Despite its excellent value, the network lags in customer support compared to no-frills competitors.

As part of Currys and Carphone Warehouse, iD Mobile features an extensive handset range, including budget and mid-range options. Its competitive pricing extends to two-year contracts, often undercutting major network prices.

iD Mobile’s popularity stems from its value for money and reliability, with approximately 80% of customers recommending it in our annual survey. That said, customer service remains a concern, with only 17% of customers reporting high satisfaction. Although better than some networks, there’s scope for improvement.

Utilising Three’s network, iD Mobile boasts extensive 4G coverage and growing 5G reach. Its 5G performance, especially in urban areas, is impressive, sometimes exceeding that of its host network. Nonetheless, its performance for audio and video streaming is not optimal, potentially affecting users with high-demand streaming needs.

A unique feature of iD Mobile is data rollover, allowing customers to carry forward unused data, enhancing its value proposition. It also offers free EU roaming, a rarity among modern networks. For additional control over costs, customers can set spending caps via the iD Mobile app or website.

Overall, iD Mobile stands out for its affordability and substantial data offerings. However, it faces challenges in customer service and specific performance aspects like streaming. Its value and flexible contracts make it attractive, but there are areas where it could improve to better compete with other services​.

Read our full iD Mobile review

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