2021 Audi A3 S Line prices

There are 213 used 2021 Audi A3 S Line cars for sale from UK dealers on AskCar, as of 5 November 2026. Typical asking price £17,000 (the median: half cost less, half cost more). The cheapest is £11,581. The middle half are priced between £15,800 and £18,300. Median mileage: about 42,000 miles.

Dealers lowered the asking price on more than a third of 2021 Audi A3 S Line cars: 86 of the 213 in the 14 days to 5 November 2026.

2021 Audi A3 S Line prices by engine and mileage

A 2021 Audi A3 S Line 1.5 petrol car typically costs £17,500, against £16,700 for the 1.4 plug-in hybrid, as of 5 November 2026.

A 2021 Audi A3 S Line 1.5 petrol car with 20,000 to 40,000 miles typically costs £18,300, against £15,500 with 60,000 miles or more.

EngineAll mileagesUnder 20,000 miles20,000 to 40,000 miles40,000 to 60,000 miles60,000 miles or more
1.5 petrol£17,500Too few for sale£18,300£17,000£15,500
1.4 plug-in hybrid£16,700Too few for saleToo few for saleToo few for saleToo few for sale
1.0 petrol£16,500Too few for saleToo few for saleToo few for saleToo few for sale

Only 12 of the 2021 Audi A3 S Line cars for sale have the 2.0 diesel engine, too few to give a typical asking price.

Typical asking prices are of 2021 Audi A3 S Line cars for sale on 5 November 2026, and are given only where at least 20 cars with a price are for sale.

2021 Audi A3 S Line against other years

A 2020 Audi A3 S Line car has a typical asking price of £16,000 and a 2022 one £18,000, as of 5 November 2026.

AskCar lists 6,826 used Audi A3 across the UK, from 2,317 dealerships.

As of 5 November 2026, AskCar lists 595,776 cars and vans from 12,945 UK dealerships, read daily from dealer websites: over 99% of UK dealer used car adverts. No dealer pays to be listed.

2021 Audi A3 S Line cars for sale now, page 1 of 5

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. 204 of the 207 cars listed here meet these rules. Pages 2 to 5 list every other 2021 Audi A3 S Line car, cheapest first, including the 3 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 6,645 priced Audi A3 adverts on AskCar as of 5 November 2026. The figures on this page describe the cars advertised, not a valuation of every 2021 Audi A3 S Line.

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 6 cars whose advertised mileage is lower than the mileage recorded at their last MOT test.

Best value 2021 Audi A3 S Line: priced furthest below the AskCar estimate

These 10 are priced 7% to 23% under their AskCar estimate. Their asking prices run from £12,999 to £18,140.

Cheapest 2021 Audi A3 S Line: the lowest asking prices

These 10 are priced £11,581 to £12,990. They have covered 84,920 to 120,530 miles.

Lowest-mileage 2021 Audi A3 S Line

These 10 have covered 11,900 to 19,757 miles. Their asking prices run from £16,499 to £20,999.

Recently reduced 2021 Audi A3 S Line: the biggest price reductions in the 14 days to 5 November 2026

The dealer lowered the asking price on each of these 10 in the 14 days to 5 November 2026. Their reductions since AskCar first saw them run from £2,000 to £4,640.

Newly advertised 2021 Audi A3 S Line: first seen by AskCar in the 7 days to 5 November 2026

These 10 are the most recently advertised. Cars first seen on the same day are listed cheapest first.

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