Five used convertible cars to buy in 2025 for under £25k with robust reliability
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With temperatures tipped to soar beyond 30 degrees across Britain this week, a cheap second-hand convertible will be a tempting proposition.
But before you start perusing the car ads for a cabriolet on a budget to enjoy the summer rays and wind-in-the-hair driving, it's important to know which are the most reliable to run to protect you from excessive repair bills.
Extended warranty data supplied by Warranty Solutions Group (WSG) covering a sample of 3,000 convertible cars reveals how many customers have claimed on their policies in the last 12 months (July 2024-June 2025).
The top five with the lowest claim rate are listed, which is based only on popular models for which 100 owners have taken out extended warranty cover.
To help you make your decision, we'll tell you how much you will need to pay for a 10-year-old example with less than 60,000 miles on the clock.
And we also reveal which convertible model you might want to avoid, with more than a quarter of owners with warranties claiming on their policies due to high repair bills.
Just one in seven owners of Audi TT Roadsters made an extended warranty policy claim to cover repair bills for their cars last year
Despite huge success, particularly when the first-generation model arrived in the late nineties, the Audi TT is no more.
The German marque pulled the plug on production in November 2023, ending 25 years of its availability.
Those on the hunt for a decent 10-year-old model can pick up a third (and final) generation TT Roadster for around £14,000 with fewer than 60,000 miles on the clock.
This gets you top down driving from cabriolet with a 2.0-litre TFSI petrol engine sending power to the front wheels via a manual six-speed transmission. All-wheel-drive variants with the S-Tronic auto 'gox will cost slightly more and those wanting more frugality - but a worse sound - can get their hands on a 2.0-litre TDI diesel variant, too.
Just one in seven owners with an extended warranty in the last 12 months have claimed on their policies, with the average cost of repairs ringing in at £505.
The only four-seat convertible to make the list of five most reliable top-down cars is the Mini
Buyers searching for a second-hand compact convertible packed with retro styling and an affordable price tag should look no further than Mini's Convertible.
You can pick up a decent 10-year-old example for around £6,000 today with the brand's tried-and-tested 1.6-litre petrol engine under the bonnet.
It's also the only model in our top five that has seating for four - though adults in the back can expect a cramped experience to say the least.
On average, one in eight extended warranty policyholders claimed for vehicle repairs to their Mini Convertible in the last 12 months - and that's based on vehicle dating back to 2004.
With an average payout of £535, the Mini Convertible is one of the more expensive cabrios to fix when something goes go wrong.
While for a long time it was considered the poor man's 911, the Boxster has cultivated a devoted following of fans, which is partly due to its reliability and relatively low running costs
The most expensive option in our list is the Porsche Boxster. With incredibly strong residual values, even a decade-old version will set used buyers back around £25,000 for a standard 2.7-litre versions of the mid-engined 981-generation roadster.
If you want to upgrade to a 3.2-litre 'S' or 'GTS', prices are even steeper.
While for a long time it was considered the poor man's 911, the Boxster has cultivated its own devoted following of fans, which is why depreciation is relatively slow and used prices remain stubbornly high.
Strong reliability - and relatively low running costs compared to other Porsche products - is another reason for its popularity.
Just over one in ten extended warranty policyholders made a claim in the last 12 months. And the claim amount on average was less than for the Mini Convertible.
Just one in 11 owners with extended warranties have claimed on their Z4 repair costs in the last year. A decade-old example will set you back around £12,000 today
BMW's Z generation o two-seat roadsters, including the Z3, haven't always had the strongest dependability track records. But the German giant - and its engineers - have tackled this issue in recent years and the Z4 has become relatively robust.
If you're hunting for a 10-year-old example, the E89 edition (which went out of production in 2016) offers good value over its G29 replacement that remains in showrooms today.
You can get your hands on a sub-60,000-mile example with a 2.0-litre petrol engine and automatic gearbox for around £12,000 today. Sending power to the rear wheels, featuring two seats and a hard-top roof, it's every bit the performance sports car.
Just one in 11 owners with extended warranties have claimed on their Z4 repair costs in the last year.
While that's an impressively low volume, the average claim amount is higher than any other motor listed, at just over £750.
The Mazda MX-5 is ranked the most reliable convertible car you can buy in Britain, based on the volume of warranty claims. A 10-year-old example - which is based on the current model - can be had for as little as £11k today
Taking the top spot is the Mazda MX-5, long hailed as the gold standard for affordable sports cars.
Its near-legendary dependability stems from Mazda’s dedication to engineering simplicity and mechanical purity that has benefitted its popular roadster for the last 35 years.
With its rear-wheel-drive layout, wonderfully engaging manual gearbox and lightweight nippiness, the MX-5 has always been a thoroughly brilliant sports car to drive that's refreshingly mechanically uncomplicated.
The current fourth-generation car launched in 2015, so a ten-year-old example is pretty much bang up to date. Buyers have the choice of two Skyactiv-G petrol engines (1.5 and 2.0 litres).
With a claim rate of just 7.7 per cent across all MX-5 models, dependability in roadster for doesn't get better than this. For the one in 13 owners who have claimed, the average payout was £456.
'The Mazda MX-5 remains a standout example – and its long-standing reputation for durability continues to be validated by surveys from What Car?, J.D. Power, and Consumer Reports in America,' explains Martin Binnee, operations director at WSG.
'It consistently outperforms expectations, reinforcing the value of engineering simplicity and mechanical integrity in an era of increasing complexity.'
With almost three in ten owners of Mercedes-Benz E-Class Cabriolets turning to their extended warranties to cover the cost of repairs, WSG ranks it the least reliable of all popular convertible models
The Mercedes E-Class is the convertible car with the highest volume of claims made by owners.
Almost three in ten drivers of the luxury four-seat cabriolet claimed on their polices in the last 12 months, which is why WSG ranked it lowest for reliability among the popular convertibles.
'While it's an undeniably luxurious cruiser, its high maintenance costs and relatively frequent faults make it a less attractive proposition for used buyers prioritising longevity and hassle-free ownership,' the provider said.
*NB: Average used prices based on 2015 models with less than 60,000 miles advertised on AutoTrader
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