Below Deck Mediterranean returns for its fifth season with Captain Sandy Yawn at the helm of the mega-yacht Wellington, cruising one of the most desired yachting locations in the Mediterranean: Mallorca, Spain. After earning the Lead Deckhand title in season 2, Malia returns as Captain Sandy's first female Bosun, a role she hopes to grow into while commanding respect from her all-male deck team. Brazilian Chef, Kiko, tries to make a good first impression while having to overcome Captain Sandy's skepticism from last charter season's galley struggles. Hannah returns as Chief Stew in a new stage of her life, but immediately finds herself challenged by an experienced Second Stew. When the first guests arrive, cracks begin to surface as Hannah attempts to maintain control of her team.

Romance is in bloom on the crew's first night out of the season, as Pete makes his move while Rob and Jess find themselves connecting on a deeper level. The second charter kicks off when guests with ties to the music industry arrive, but unforeseen circumstances immediately put the Wellington crew behind the eight ball. Meanwhile, Pete's attitude forces Malia into a difficult confrontation, and tensions between Hannah and Lara take a surprising new turn.