Dubbed Scotland's Route 66, NC 500 loops around the north Highlands' coast and interior.
The seven included Commonwealth Games cyclists Lee Craigie and Anne Ewing and British 24-hour mountain bike champion Rickie Cotter.
The time trial over Saturday and Sunday started and finished in Inverness.
The other riders were author and travel blogger Emily Chappell, transcontinental cyclist Gaby Leveridge, plus Zara Muir and Jo Thom, winners of the women's pairs event at this year's Strathpuffer endurance ride near Strathpeffer.
Their time sets a new record for cycling the route.
Scottish endurance cyclist Mark Beaumont previously completed the NC 500 solo in 37 hours 58 minutes.
The NC 500 features several challenging ascents and descents, including the Bealach-na-Ba at Applecross.
The unclassified road rises to about 626m (2,053ft) over about four miles (8km).
Seven women cyclists have set a time of 36 hours to complete the gruelling 518-mile (833km) North Coast 500 in a non-stop team time trial.