Diana Nyad swam up to the beach just before 2 p.m. EDT, about 53 hours after she began her journey in Havana on Saturday. As she approached, spectators waded into waist-high water and surrounded her, taking pictures and cheering her on.
"I have three messages. One is, we should never, ever give up. Two is, you're never too old to chase your dream. Three is, it looks like a solitary sport, but it is a team," she said on the beach.
"I have to say, I'm a little bit out of it right now," Nyad said. She gestured toward her swollen lips, and simply said "seawater."
Her team said she had been slurring her words while she was out in the water. She was on a stretcher on the beach and received an IV before she was taken by ambulance to a hospital.
"I just wanted to get out of the sun," she said.
It was Nyad's fifth try to complete the approximately 110-mile swim. She tried three times in 2011 and 2012. Her first attempt was in 1978.
"It's historic, marvelous," said Jose Miguel Diaz Escrich, the Hemingway Marina commodore who helped organize the Cuba side of Nyad's multiple attempts.
"I always thought she could do it given her internal energy, her mental and physical strength, her will of iron," said Diaz Escrich, whom Nyad has described as a longtime friend.
"More than the athletic feat, she wants to send a message of peace, love, friendship and happiness ... between the people of the United States and Cuba," he said.
Her last try was cut short amid boat trouble, storms, unfavorable currents and jellyfish stings that left her face puffy and swollen.
This time, she wore a full bodysuit, gloves, booties and a mask at night, when jellyfish rise to the surface. The new silicone mask caused bruises inside her mouth, making it difficult for her to talk, she told her team when she was about 2 miles from land.
Doctors traveling with Nyad were worried about her slurred speech and her breathing, but they didn't intervene, according to Nyad's website.
Nyad's journey began Saturday morning when she jumped from the seawall of the Hemingway Marina into the warm waters off Havana. She stopped from time to time for nourishment, but she never left the water.
The support team accompanying her had equipment that generated a faint electrical field around her, which was designed to keep sharks at bay. A boat also dragged a line in the water to help keep her on course.
Sumaya Haddin, of Miami, had been tracking Nyad's swim before her family's trip to Key West this weekend. She was surprised to see Nyad's flotilla from a parasail off Smather's Beach on Monday morning. She thought Nyad wasn't due for another day.
"You couldn't see her, you could just see the boats. It was very exciting," she said.
Haddin said Nyad still had her fighting spirit when she got to the beach. "Getting into the ambulance, she had her peace sign up, her fist up. She was still fired up."
Australian Susie Maroney successfully swam the Strait in 1997 with a shark cage, which besides protection from the predators, has a drafting effect that pulls a swimmer along.
In 2012, Australian Penny Palfrey swam 79 miles toward Florida without a cage before strong currents forced her to abandon the attempt. This June, her countrywoman Chloe McCardel made it 11 hours and 14 miles before jellyfish stings ended her bid.
In 1978, Walter Poenisch, an Ohio baker, claimed to have made the swim using flippers and a snorkel. Critics say there was insufficient independent documentation to verify his claim.
Nyad first came to national attention in 1975 when she swam the 28 miles around the island of Manhattan in just under eight hours. In 1979 she swam the 102 miles from North Bimini, Bahamas, to Juno Beach, Fla., in 27.5 hours.
Nyad is also an author of three books, a motivational speaker and has been a reporter and commentator for NPR.
Associated Press writer Anne-Marie Garcia in Havana contributed to this report.