It has been six weeks since Kelsey Pfendler, a Grand Canyon river-rafting guide, launched her 21-foot rowboat off the craggy shores of Central California into the Pacific Ocean.
Late on Friday night — more than 2,300 miles and 43 days later — she pulled into Ala Wai harbor in Honolulu, docked her boat and stepped back onto land, breaking several records in the process.
Ms. Pfendler, 32, received a hero’s welcome from hundreds of fans lined up in the harbor. Thousands more congratulated her on social media, where she has been posting daily videos documenting her progress.
She appears to be the first American woman to have successfully rowed solo from California to Hawaii — as well as the youngest person, and the fastest, to have completed that route without assistance, according to data from the Ocean Rowing Society International.
Her final time was 43 days, 17 hours, 55 minutes and 59 seconds, she wrote on social media.
The next-fastest woman to complete the same route solo and without assistance took just over 86 days. She did it in 2020.
“We all had our phone lights on guiding her in to the harbor, sort of like guiding stars,” said Sarah Maune, 33, a content creator who posts cooking videos under the name Sarah Kraffty and whose vacation trip to Hawaii happened to coincide with Ms. Pfendler’s finish. “Everyone was chanting her name.”
Ms. Maune added: “I followed her social media journey from the beginning, so I knew I had to be there in person. It was amazing to witness.”
Ms. Pfendler, who did not respond to multiple requests for comment, has been a professional river-rafting guide since she turned 18 and now leads trips along the Colorado River in the Grand Canyon, according to her website.
She turned her expedition into an online movement, amassing hundreds of thousands of followers who tuned in to daily video updates she recorded from her boat.
The videos from her rowing expedition show her doing everything from swimming in the ocean to discussing the psychological stress of high-endurance sports.
On June 6, she demonstrated how she turns seawater into drinkable fresh water. On June 10, she explained how she was struggling to row every night until around 4 a.m., sleeping only about two and a half hours. On June 16, she did her laundry on the boat, hanging it from makeshift clotheslines.
“It’s an enormous achievement to complete an ocean row, and to break a speed record is another enormous achievement on top of it,” said Fiann Paul, a record-holding ocean rower and the president of the Ocean Rowing Society International, which adjudicates ocean-rowing achievements for the Guinness World Records.
Mr. Paul said that while the records weren’t official yet, his society’s data indicated that Ms. Pfendler’s row was the fastest completed solo and unassisted on the Mid-Pacific route she took, and that she was the youngest to have completed it solo.
He added that other rowers, including younger ones, have completed longer routes across the entire Pacific Ocean. He noted, too, that different rowers use different classes of boats designed for different speeds, which can make comparing records difficult.
Duncan Roy, an ocean rowing coach who in 2020 circumnavigated Britain in Ms. Pfendler’s current boat, which is named Lily, said that Ms. Pfendler’s achievement is “really special” and that she’s “a great ambassador” for ocean rowing.
“Everyone in the sport has been talking about her and following her journey,” he said. “To be able to have the cognitive ability to deliver those updates and do the storytelling — it’s extraordinary.”
Neil Bergenroth, another ocean rowing coach, called Ms. Pfendler’s row “an incredible feat physically and mentally.”
“It’s a balance between how much do I sleep versus how much do I continue to row,” said Mr. Bergenroth, who spent two and a half years training an Irish man who this year won a 3,000-mile rowing race across the Atlantic Ocean. “It’s a very different animal than the Olympics events, which take five or six minutes to do.”