2021 BMW X3 prices under £20,000

There are 20 used 2021 BMW X3 cars for sale under £20,000 from UK dealers on AskCar, as of 11 November 2026. Typical asking price £18,400 (the median: half cost less, half cost more). The cheapest is £16,295. The middle half are priced between £17,600 and £19,800. Median mileage: about 86,000 miles.

Dealers lowered the asking price on more than half of 2021 BMW X3 cars under £20,000: 13 of the 20 in the 14 days to 11 November 2026.

AskCar lists 3,106 used BMW X3 across the UK, from 1,225 dealerships.

As of 11 November 2026, AskCar lists 593,449 cars and vans from 12,847 UK dealerships, read daily from dealer websites: over 99% of UK dealer used car adverts. No dealer pays to be listed.

2021 BMW X3 cars for sale now under £20,000, page 1 of 2

This page picks out up to 10 cars in each of these groups: best value, cheapest, lowest mileage, recently reduced and newly advertised. A car in more than one group is listed in full once. The groups pick only from cars with photos and an AskCar estimate, priced at £500 or more and no more than 25% under that estimate. 18 of the 19 cars listed here meet these rules. Page 2 lists every other 2021 BMW X3 car, cheapest first, including the one the groups do not pick from.

The AskCar estimate is our expected asking price for that one car, from its model, age, mileage and specification, using the 3,043 priced BMW X3 adverts on AskCar as of 11 November 2026. The figures on this page describe the cars advertised, not a valuation of every 2021 BMW X3.

Each car: year, make, model, engine and trim, power, gearbox, fuel, body, doors, colour; mileage; price and its changes; how the price compares with the AskCar estimate; emissions standard and ULEZ compliance where it holds; MOT; dealer and town; AskCar page. Each car's AskCar page has its full price history and cheaper cars like it.

This list leaves out 1 car whose advertised mileage is lower than the mileage recorded at its last MOT test.

Best value 2021 BMW X3: priced furthest below the AskCar estimate

These 10 are priced 4% to 7% under their AskCar estimate. Their asking prices run from £17,230 to £20,000.

Cheapest 2021 BMW X3: the lowest asking prices

These 10 are priced £16,295 to £18,650. They have covered 64,847 to 114,230 miles.

Lowest-mileage 2021 BMW X3

These 10 have covered 56,373 to 87,665 miles. Their asking prices run from £17,699 to £20,000.

Recently reduced 2021 BMW X3: the biggest price reductions in the 14 days to 11 November 2026

The dealer lowered the asking price on each of these 10 in the 14 days to 11 November 2026. Their reductions since AskCar first saw them run from £700 to £3,213.

Newly advertised 2021 BMW X3: first seen by AskCar in the 7 days to 11 November 2026

This car is the most recently advertised.

BMW X3 by gearbox, fuel and body

BMW X3 under £20,000 by gearbox, fuel and body

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