The Whistle lifeguard is a whistle person who is staffed in the Wet Pipes Water Park. He is one of the many whistle people who work in the water park. He instructs people when to slide down the slide and makes sure everyone obeys the rules.
In the episode "Water Park Prank," he tries to ensure that Ice King slides down all the way to the end of the slide without bouncing back up. This was all part of a prank set up by Finn and Jake, however, the Lifeguard was unaware of this as Finn managed to slide all the way down without Jake blocking him from reaching the end. When Ice King assaults Finn for being responsible the lifeguard whistles with his body and ask Ice King to leave. He is later seen helping other whistle people carry the tied up Ice King out of the water park.
The lifeguard's whole body is a red whistle as he is a whistle person. He wears a green shirt and has a lifeguard logo on the side of his body indicating that he is a lifeguard. He has brown hair which falls mostly his eyes. He wears white shoes.
- "Water Park Prank" (debut)
He is loyal to his job and makes sure that everyone obeys the rules. He instructs everyone and tells them what to do and what not to do. When Ice King assaults Finn, he quickly whistles loudly to stop the situation and later is seen helping other whistle staff escort the tied up Ice King out out of the water park. He also gets annoyed when people disobey the water park rules.