David is the cute, honest, matter-of-fact boy-next-door who is always happy to help out. David works at the Ocean Cafe, which his father owns, and which is well liked by the community. His older brother, Joe, appears to constantly ask him to do things for him. Joe also appears to supply the Ocean Cafe.
There's instant puppy-love chemistry between David and Sirena, but Sirena resists, knowing that getting involved with David would only complicate things.
David's the sort of trustworthy, dependable, guy who Sirena thinks could be entrusted with their secret. Not that she's going to tell him. And although he might suspect something strange is going on with Sirena and her friends, he minds his own business--he is just happy to be able to spend time with Sirena. Ultimately, In season 2 episode 26, Sirena reveals to him that she is a mermaid. He reacts with shock and excitement.