Organisers said the incident occurred on the morning of May 3 when an athlete was guiding a tourist during a flyboard session and the equipment malfunctioned, causing both to lose balance and fall into the water.
The female tourist resurfaced safely, while the athlete remained submerged longer and was pulled ashore unconscious with signs of near-drowning.
Both were given first aid and taken to hospital, where their conditions later stabilised and were not considered life-threatening.
Flyboard performances had been launched on April 30 at Ky Lan Lake before being relocated to Nui Lo Lake on May 3.
The suspension would remain in place while all technical procedures, operating conditions and safety measures were reviewed before any resumption.
The incident has prompted renewed calls for tighter safety standards for adventure tourism activities, particularly newly introduced attractions.