Descended from a Maltese sea captain, Caffari grew up in Rickmansworth, Hertfordshire and attended St. Clement Danes School. Caffari studied at Leeds Metropolitan University and became a PE teacher for 5 years before beginning her sailing career.
Caffari trained at UKSA (based in Cowes, Isle of Wight) completing her Yachtmaster course and a range of ocean qualifications. Caffari then worked for Formula 1 Sailing, first as a skipper and then as the manager of their fleet of Farr 65s in the UK and the Caribbean.
She then took part in the ten-month Global Challenge race, which departed on 3 October 2004. Held every four years, this race takes a fleet of one design (or matching) steel yachts, crewed by amateur sailors who have paid to take part, round Cape Horn and through the Southern Ocean where winds can exceed 70 knots. That race also takes the westabout route.
Caffari was the skipper of the yacht Imagine It. Done. One crewmember needed to be airlifted off in the Southern Ocean, creating the largest Southern Ocean Rescue of all time for the New Zealand Rescue Service. The race also saw the team develop from having to retire from the second leg of the race to finishing on the podium in leg six.
On 20 November 2005, she set off on her attempt to single-handedly circumnavigate the world against the prevailing winds and currents. She finished on 18 May 2006, at 17:55pm, after 178 days at sea. Her voyage was sponsored by Aviva.
On 2 December 2006, she was a runner up for BBC South Sports Personality of the Year. She did win the Tenon Yachtsperson of the Year award.
In January 2007 Caffari announced that she would be taking part in the Vendée Globe 2008/09 singlehanded round the world yacht race, again sponsored by Aviva. In March 2007 she announced a technical partnership with Mike Golding to allow both the British entries in the Vendée Globe to work together.
In September 2007, Caffari's autobiography Against the Flow was published by Adlard Coles Nautical.
In December 2007 she had to be rescued by Royal Navy frigate HMS Northumberland after dismasting in severe weather off northwest Spain whilst competing singlehanded in the Transat Ecover B2B Race.
In May 2008 she competed in the Artemis Transat race across the Atlantic Ocean from Plymouth to Boston, against the prevailing winds.
In February 2009 Dee Caffari completed the Vendee Globe race and set a new record becoming the first woman to sail solo, non-stop, around the world in both directions.
In March 2009, Caffari's autobiography Against the Flow was published in paperback with an additional chapter charting the lead up to her Vendee Globe entry and subsequent world record achievement.
In June 2009 Dee Caffari set a new record for circumnavigating Britain and Ireland after crossing the Solent finish line on her Open 60 Aviva having beaten the existing record by 17 hours.
Caffari was a crewmember aboard Team SCA for the 2014–15 Volvo Ocean Race. She will skipper the Turn the Tide on Plastic boat in the 2017–18 Volvo Ocean Race.
Dee has been an enthusiastic supporter of charities such as Toe in The Water (using competitive sailing to re-inspire injured servicemen), and Sail 4 Cancer.
In October 2011, Dee Caffari accepted the role as the new patron for the charity Gosport and Fareham Inshore Rescue Service which is an independent lifeboat station based in Stokes Bay local to where Dee Caffari lives.
Dee Caffari sits on the Operations Board of the Royal National Lifeboat Institution, and is an Honorary Commander in the Royal Navy.