Hundreds of people from across the country are preparing this morning to follow in the soggy footsteps of notorious Alcatraz Island escapees by diving from near the former prison and swimming across the San Francisco Bay.

About 400 swimmers have registered to take part in the third-annual Orca Alcatraz Swim Challenge today, according to organizers from Tri-California Events.

The race begins when swimmers jump off of the California Hornblower yacht just off-shore from Alcatraz Island and ends once they reach Crissy Field’s East Beach.

“The Alcatraz Challenge offers an epic way to get an up-close look at the site of infamous Alcatraz Island Federal Penitentiary, the Golden Gate Bridge and a unique view of San Francisco’s world-renowned skyline,” Terry Davis, Tri-California Events’ CEO, said in a statement.

Swimmers will brave frigid water temperatures and moderate currents under the guidance of a water safety team, event organizers said.

Many race participants were able to take part in swim orientations Saturday to learn more about Bay currents and tides, race landmarks and other elements to expect during the 1.5-mile journey.

Swimmers are set to jump promptly at 8 a.m.