Albums by Adele, Abba and Ed Sheeran helped vinyl sales in the UK top five million for the first time since 1991.
Almost a quarter of the albums bought this year (23%) were on vinyl, with Abba's Voyage the biggest-seller.
It marks the format's 14th consecutive year of growth, with sales up by 8% on 2020.
Sales of CDs continued to fall. Just 14 million discs were bought – the lowest figure since 1984, one year after the format was introduced in the UK.
- Abba top charts with first album for 40 years
- How vinyl records are trying to go green
- 'I've got through lockdown by playing 300 vinyl records'
However, the drop-off in CD sales was smaller than in recent years, with sales decreasing by 12%, compared to nearly a third in 2020.
That's partly because artists like Abba and Adele appeal to older listeners, who still prefer the format.
Music industry body the BPI said it hoped that the reduced demand for CDs was "bottoming out" after years of decline.
The vinyl resurgence continued in 2021 despite serious delays in manufacturing, caused by a combination of Covid, supply-chain issues and labour shortages, as well as a scarcity of raw materials like PVC and paper products.
One report blamed Adele for further clogging up the world's vinyl plants with pre-orders for her new album, 30 – but her order of 500,000 records only accounted for 0.3% of the LPs pressed this year. (A bigger problem is that demand for vinyl outstrips manufacturing capacity by a factor of 2:1).
In the end, Adele's return was eclipsed by that of Abba, who took the world by surprise in September by announcing their first album of new material in more than 40 years.
Titled Voyage, it shifted 29,891 copies in its first week on sale, following an extensive pre-order campaign that gave fans early access to tickets for the Swedes' virtual concerts next year.
Voyage duly became the fastest seller on vinyl this century, according to the Official Charts Company.
Cassette sales, while representing a tiny fraction of the music market, also increased for a ninth consecutive year.
Final figures for 2021 are likely to show that around 190,000 tapes were purchased in the past 12 months, up by around 20% year on year.
It's the format's most successful year since 2003, when Now 54 was the year's biggest seller on cassette.
The revival arguably has more to do with marketing than any real appetite for the format, however.
Most artists now offer signed cassettes on their official website, frequently in bundles with CD or vinyl copies of the same album.
Fans often have no choice but to accept the cassette as part of the bundle; and each copy of the record handily counts as a separate sale on the official chart.
Sales of physical formats are dwarfed by the popularity of streaming, which accounted for 80.6% of music consumption in 2020.
Even so, having an album available on CD and vinyl plays a pivotal role in artists reaching number one.
Adele's 30, for example, has seen 75% of its chart sales attributable to physical format purchases during its five-week reign at the top of the charts.
Despite that, streaming's share of the market is thought to have increased further this year.
The BPI will report that data, along with the year's final music consumption figures, on 4 January,
Follow us on Facebook, or on Twitter @BBCNewsEnts. If you have a story suggestion email email@example.com.