The embassy yesterday issued the alert following the sexual assault of a US citizen by a man on one of the watercraft on Cabbage Beach.
The Royal Bahamas Police Force said a 26-year-old man was taken into custody as a suspect in the January 2 attack.
The embassy said there had been five sexual assaults of US citizens by jet-ski operators in Nassau since July. The embassy banned its staff from using jet-ski rental companies because of insufficient regulation. It recommended US citizens not use them either.
It noted in a statement that all jet ski operators are subjected to "full vetting" by police but added that "despite our efforts, challenges do remain." Ministry officials planned to discuss the issue with operators and business owners today.
The embassy expressed similar concerns last year about jet-ski operators as well as rising crime in general in the Bahamas.