In Emerald Bay, Florida, Lt. Mitch Buchannon and his team of lifeguards, including second-in-command Stephanie Holden and veteran C. J. Parker, protect the beaches and the bay as part of an elite division known as Baywatch. Having made over 500 rescues in his career, Mitch is beloved by the community, to the annoyance of local beat cop Garner Ellerbee and Mitch’s superior, Captain Thorpe. During one of his morning patrols, Mitch discovers a small pouch of flakka drug washed up near the Huntley Club, which is now under the ownership of Indian businesswoman Victoria Leeds, who has been secretly bribing city councilman Rodriguez and others in efforts to increase her stake in the bay.
At the tryouts for prospective lifeguards, three people stand out: surfer Summer Quinn, an old friend of Holden; Ronnie Greenbaum, a chubby computer nerd with a mutual crush on C. J.; and Matt Brody, a former Olympic gold medal swimmer who fell from grace to grass after vomiting during a relay race. Summer and Ronnie both pass the trials, but Brody refuses to participate, insisting his Olympic status and recommendation letter entitles him to have a place on the team. Mitch challenges Brody on a course of the former’s choosing, but a drowning woman and her kids interrupt the challenge and they rush to save her. Mitch learns Brody has to perform community service as part of an unspecified plea deal, and that Thorpe insists rehabilitating Brody’s image is necessary to convince the city not to further cut Baywatch’s funding.
When a private yacht catches fire, Brody disobeys orders and dives directly under the flames, causing Holden and C. J. to have to save him. The occupants are evacuated, except for the deceased councilman Rodriguez. Ellerbee disapproves of Mitch’s further investigative actions. Mitch and the gang attend a party held by Leeds to look for more evidence but without much luck as Brody makes a fool of himself getting drunk. Mitch, Brody, and Summer later infiltrate the city morgue, where they record two of Leeds’ men planting a falsified autopsy report to cover up the fact that Rodriguez was murdered on her orders. Unfortunately, they are discovered, and though Mitch manages to subdue and capture one of them, the recording is destroyed and Ellerbee is forced to release their suspect on a lack of evidence. Angered, Thorpe threatens to fire Mitch if he oversteps his authority again.
Convinced that Leeds is running drugs out of the Huntley, Mitch and Brody go undercover and sneak into the club kitchen, where they witness her workers retrieving the drugs from barrels of fish and processing them. They contact Ellerbee, only to learn that another body has been found on the beach. Thorpe, enraged that Mitch essentially deserted his post, fires him and names Brody as the new lieutenant. Brody accepts the job reluctantly, and Mitch takes a job as a cellphone salesman.
After finding another pouch of flakka on the beach, Brody steals the second victim’s report from Ellerbee and brings it to Summer, who confirms his suspicion that the man was murdered. Ronnie, upon recognizing the victim as his friend Dave, helps Brody hack into Leeds’ servers, revealing her plan to privatize the entire beach by systematically buying out or eliminating every competing business owner.
The team infiltrates a private party on Leeds’ personal yacht, discovering how she’s been using the hull to smuggle the drugs. Brody is captured and placed in a bait cage to be drowned, and a gloating Leeds reveals that she bribed the corrupt Thorpe to set Mitch up so he could justify firing him before pushing the cage into the water. Just before Brody drowns, Brody’s love interest and fellow lifeguard Summer, who he may or may not be kissing underwater. One minute he’s kissing her, and the next he’s kissing Mitch who appears and saves him. The two catch up to Leeds, while Ronnie and C. J. launch fireworks to prevent her escape helicopter from landing. Just as they run out, a wounded Mitch, having intentionally stung himself with a sea urchin to boost his adrenaline, uses a Roman candle to blow Leeds up, saving Brody once again. Ellerbee arrives and takes Leeds’ henchmen into custody, apologizing to Mitch for doubting him. Thorpe arrives and begins to berate Mitch for returning to the beach. In response, Brody punches Thorpe in the face. Thorpe is subsequently arrested for his role in Leeds’ plan.
In the aftermath, Ronnie and Brody begin relationships with C.J. and Summer respectively. Mitch, having been reinstated, formally inducts Summer, Ronnie, and Brody into Baywatch and introduces them to their new captain, Casey Jean (Pamela Anderson).
