Captain Sonny Jennings and his core team of lifeguards monitor the dangerous Hawaiian waters; new lifeguard recruits compete to join Sonny’s district; Sonny and his family grieve after the loss of his nephew; Em reveals a romantic past with Will.

A flash flood sweeps a young tourist away from her family and out to deep sea; going against Sonny’s wishes, Em takes a bold risk and places her own life in danger in hopes of rescuing the lost -at-sea tourist.

Em works to earn the team's respect when she is left in charge and Hina and Kainalu juggle multiple beachside emergencies; Will's fiancee pays him a visit at work; Sonny opens up to a former lifeguard about his trauma since losing his nephew.

College kids get trapped in a collapsed sandpit; Sonny, Will and Laka race to rescue people stranded after a shark attack; Will learns if he made the cut for the firefighter job he has been pursuing.

The North Shore community comes together for Rocky's paddle out; Hina thinks about switching districts; Laka, Will and Kainalu try to save a beachgoer that accidentally speared his own foot; romance heats up between Sean and Em.

An influencer gets swept into the ocean while trying to film a new video; Kainalu and Hina discuss setting boundaries within their home; Mayor Emerson makes good on his word with Captain Sonny; Jenn finally agrees to go on a date with Laka.

Sonny, Em, Will and Laka look for missing paragliders that were pushed into the ocean by a down draft; Kainalu invites Hina to a party with his ex-girlfriend; Jenn doesn't think Laka is serious enough for her; Sonny puts in his notice to retire.

Christmas cheer is in the air as the lifeguards prepare for their annual holiday toy drive; while surfing, a local grandpa has a heart attack and is rushed to the hospital; Sonny tells Laka he is not ready to become a lieutenant.