Fourth generation (8Y, 2020-present) · Premium family hatchback
The Audi A3's driver-side floor uses a pair of round factory retention posts rather than the twist-lock cams found on some other VW-group cars, so check the retention type on a universal mat. The Sportback and the Saloon share the 8Y front footwell, so front mats fit both, and the rear mats are shared as well.
Second generation (F3, 2018-present) · Premium compact crossover
The current Q3 (F3, 2018-onwards) uses one front footwell across every UK trim, but the rear bench slides 150 mm fore-aft. That means a rear liner cut to the "seats fully back" position leaves a small gap when the bench is slid forward for extra boot.
Three products we would look at first in this category. Fit for your Audi still comes first: check the compatibility list on the listing against your exact model and year, and read the model guide above.
Amazon Basics2-Piece All-Season Rubber Floor Mats
Front pair in trim-to-fit rubber; a cheap way to protect the original carpet mats.