Seafoam is a young adult pegasus who lives just outside of Fillydelphia on Baycoat Beach. He resides inside a tall lighthouse atop a small cliff, and overlooks the entirety of the shore. On this beach, he works as a caretaker and lifeguard.

Seafoam was raised mostly by his father, as his mother suffered from post-partum depression after having him. She wanted nothing to do with him for the first few years of his life. It wasn't until he was in school that she realized he had inherited her love of the ocean and sealife, and tried to bond with him. As an adult, their relationship isn't perfect, but he understands why she was troubled.

While checking the beach one evening, Seafoam encountered an unconscious changeling. Seafoam considered alerting authorities, but guilt began to eat at him. Changeling or not, someone was helpless on his beach. He was obligated to help. He took the changeling inside and nursed it back to health. Once it awoke, it introduced itself as Ziof Zap, prince of a very distant changeling colony. He wasn't here to attack, he was searching for adventure and a mate. Knowing he couldn't just let him wander Equestria, Seafoam begrudgingly offered Ziof Zap a room.

Seafoam is a very kind and caring pony with a lot of patience. He likes to believe there's good in everything, and will make sacrifices for the well-being of others. While he does get angry from time to time, be believes holding a grudge or lashing out is unhealthy. To release negative feelings, he meditates on the beach.