More than 700 people have braved a chilly Hobart morning for a nude swim in the River Derwent to mark the winter solstice.

As the sun started to hit the horizon hundreds of adventurous swimmers hit the water, which was just 11 degrees Celsius.

They threw towels and modesty aside as the outside temperature hovered around 7C.

The nude swim, part of the Dark Mofo winter arts and music festival, attracted more than twice the number of swimmers in last year's inaugural event.

The swim is restricted to over 18s.

The oldest participant, an 87-year-old woman, returned this year for her second dip.

Long Beach in Sandy Bay was not only bustling with nude swimmers but dozens of spectators who cheered them on.

Fire drums were set up along the beach to warm them after their brief dip.

Those who emerged from the water found it exhilarating.

"It is as cold as you expect it to be. The water's like needles in your skin," said one swimmer.

"All just tingly ... [you] just feel alive. You hit the water and you just go, 'Woah!'"

The festival's executive producer Kate Gould said the event exceeded expectations.

"We've been overwhelmed with responses, far more people than we ever expected," she said.

"We knew we had 500 registrations. We sometimes get drop off from the registrations to people getting up in the morning and knowing it's far too cold, they don't want to go swimming, but this year we actually exceeded that number.

"I think the nude swim is certainly part of the Hobart event calendar from now on."

The Dark Mofo festival, which has run for two weeks, attracted record crowds.

It is estimated 35,000 people attended a medieval-themed banquet over three nights on Hobart's waterfront.

The Tourism Industry Council's Luke Martin says hotels have been full and Dark Mofo has put Tasmania on the map as a winter holiday destination.

"The concept that Hobart has a weak winter period is now starting to be disproven," he said.

The tourism industry hopes its good run will continue next month with the Festival of Voices.