Allam broke the previous record of 5.35 miles, set by U.S. swimmer Benjamin Katzman in 2021.
The record-breaking swim took Allam about six hours to complete.
"During the training, I used to attract curious glances when I have the handcuffs on. To avoid drawing too much attention, I prefer to swim in quieter areas, typically near the limit line of the beaches, although I still receive some stares," Allam told GWR.
Allam said he might someday be able to break his own record, as he is still perfecting the technique he calls the "double-arm pull and modified sidestroke."
"The feeling of being among the record-breaking elite gives me a sense of being a superhero, and it drives me to maintain my position in the records for as long as possible," he said.