Sam is a 30-year-old human resources consultant who lives an orderly, highly controlled life in Manhattan. She strives for predictability to distance herself from the passionate, artistic teenager she used to be. Returning to her family's beach house in Oak Shore challenges her carefully constructed adult facade, bringing her face-to-face with the memories she tries to ignore.

Wyatt is Sam's childhood best friend and first love. He currently lives in Los Angeles where he works as a mechanic and pursues a music career. He possesses an easygoing, empathetic demeanor that contrasts with his difficult upbringing. His return to the Long Island summer house next door reawakens a flood of shared memories.

Jack is Sam's disciplined, predictable fiancé. Working as a doctor in Manhattan, he represents the safe, orderly adult lifestyle Sam has curated for herself. He adheres to strict routines, from gym schedules to sun protection, and approaches life with a straightforward, practical mindset that occasionally clashes with the relaxed atmosphere of a beach town.

Bill is Sam, Travis, and Gracie's father, as well as a university professor in Manhattan. During his summers in Oak Shore, he embraces a relaxed, free-spirited lifestyle and spends time painting. He maintains a warm presence within the family while carrying private regrets about past neighborhood conflicts that fractured the community dynamic.

Laurel is a university professor and the matriarch of the Holloway family. During the summer months, she leans into a casual, creative beach lifestyle that contrasts with her city persona. She is observant of her children's emotional states and gently encourages her daughters to seek out happiness over safety.

Gracie is Sam and Travis's 12-year-old sister, born years after them. She is energetic, loves the beach, and maintains an easy, friendly rapport with their neighbor Wyatt. As the youngest member of the family, she often serves to bridge the gap between Sam's childhood memories and her current reality.

Travis is Sam and Gracie's older brother. He lives on Long Island year-round with his partner Hugh. He is integrated into the local community and acts as a grounding, protective presence for his family. He understands the unspoken history between Sam and Wyatt and tries to watch out for his sister's well-being.

Frank is Wyatt and Michael's father. Following a tumultuous marriage, he divorced and moved back to Florida full-time. His physical absence and emotional distance leave a lasting impact on his sons, forcing them to rely heavily on each other as they grow up.

Marion is Wyatt and Michael's mother. She previously spent summers in Oak Shore before a series of personal conflicts and a subsequent divorce fractured her family. She now rents out the Long Island property, leaving behind a complicated legacy for the neighbors and her sons.

Michael is Wyatt's older brother. He spent his childhood summers on Long Island alongside the Holloways. He now lives with Wyatt in Los Angeles, sharing a strong sibling bond forged through their parents' difficult marriage and ultimate separation.

Hugh is Travis's partner. He is a supportive and integrated member of the extended Holloway family who regularly participates in their Long Island summer dinners and beach gatherings.

Eleanor is Sam's boss at the Manhattan human resources firm Human Corps. She is calculated, highly controlled, and represents the strict professional order that Sam strives to maintain in her daily adult life.

Donna is Jack's mother. Like her son, she prefers a traditional and orderly lifestyle. She brings a critical, country-club perspective to the more relaxed, slightly messy charm of the Holloways' beach community.

Glen is Jack's father. He shares his family's preference for upscale, predictable settings and arrives in Oak Shore to evaluate local venues with a skeptical eye toward the beach town's casual atmosphere.

Dr. Judy is the therapist Sam saw during her teenage years following her heartbreak. She provided clinical, detached perspectives on Sam's emotions, encouraging her to view intense youthful feelings as unhealthy obsessions.