Woolf's novels get most of the attention, but she was running a second, parallel body of work for almost three decades that most readers never open.

The Direct Answer
Yes. She kept a diary from 1915 until four days before her death in 1941, filling what became five published volumes, and treated it as a distinct practice from her fiction rather than notes toward it.
Anne Olivier Bell's edited edition, The Diary of Virginia Woolf, runs to five volumes and nearly two thousand pages, covering just short of twenty-six years.

A Different Kind of Writing, on a Different Schedule

Woolf wrote her novels in the mornings, in the garden lodge at Monk's House or in whichever room served that purpose earlier in her life. The diary belonged to a different part of the day, usually written up after tea, in a faster and looser hand than the fiction ever got. She used it less to draft scenes or solve plot problems than to keep a writing muscle warm between the harder sessions of actual fiction.

The habit started in 1915 and ran, with some gaps during her worst periods of illness, until four days before she died in 1941. Twenty-six years is a long time to keep any daily practice going, longer than most of her novels took to write combined. The entries range from a few lines to several pages, and the tone shifts constantly: gossip about visitors, arguments with reviewers, the weather, and, running underneath all of it, a writer taking her own temperature.

What the Diary Was For

In an entry from 1919, Woolf described the value of writing this way for her own eye only, saying it loosened the ligaments, meaning it kept her sentence-making flexible in a way the more careful work of a novel didn't allow. But the diary did something else too, on the days when the fiction wasn't the only thing on her mind.

I meant to write about death, only life came breaking in as usual.

Virginia Woolf, diary entry, 17 February 1922

That line gets quoted often for how neatly it captures the tension between a writer's intentions and whatever the day actually hands her. It's also just accurate reporting. Read enough of the diary and you see how often Woolf sat down meaning to write about one thing and ended up somewhere else altogether, because a visitor arrived, or a review upset her, or the light did something worth noting. A novel rarely allows that kind of drift. Woolf's diary was built for it, the one place on her schedule where following a stray thought counted as success rather than a detour.

For the rest of how her days were structured, see the full Virginia Woolf writing routine.

What You Can Steal