American Ledecky, who has also won 15 world championship titles on top of her Olympic medal haul, finished in 15:42.92, leading a field of US national team and junior team swimmers.
Her time is the fastest in the world this year by more than 17 seconds, a statement of Ledecky’s supremacy before the 1500m freestyle is added to the women’s Olympic program at Tokyo 2020.
Ledecky’s margin of victory equated to more than half the length of the pool as she finished ahead of Ashley Twichell (16:04.29) and Erica Sullivan (16:07.66).
“It’s great. It’s always good when the top swimmers are together and race each other, so it’s fun.”
Ledecky, who holds world records in the 400m, 800m and 1500m freestyle, will be hoping to win more silverware at this year’s Olympics having claimed four golds and a silver in Rio.
When facilities closed down last year amid the pandemic, Ledecky said she ended up swimming in backyard pools in small groups.
The TYR Pro Swim Series in San Antonio takes place from March 3-7 as swimmers prepare for the Olympic trials in June.
In the men’s 1500m freestlye on Wednesday, open water specialist Jordan Wilimovsky won in a time of 15:15.28 with Will Gallant (15:20.39) in second.