Sabrina travels to Australia's Great Barrier Reef with her best friend Gwen, a fellow witch from England, for a week-long vacation where they try to help protect a hidden mermaid colony whose habitat is threatened by ocean pollution, and by a local marine biologist determined to find the colony as his claim to fame. While Sabrina finds romance with a "merman" from the mermaid colony, Salem the cat finds a possible romance with another witch-turned-into-a-cat, named Hilary, but finds Sabrina's problems interfering with his plans.
| Actor | Role |
|---|---|
 Melissa Joan HartSabrina Spellman | Sabrina Spellman |
 Tara StrongGwen | Gwen |
 Scott MichaelsonBarnaby | Barnaby |
 Lindsay SloaneFin | Fin |
 Nick BakaySalem Saberhagen (voice) | Salem Saberhagen (voice) |
 Peter O'BrienDr. Julian Martin | Dr. Julian Martin |
 Rebecca GibneyHilary Hexton, the Cat & Woman | Hilary Hexton, the Cat & Woman |
 Conrad ColebyJerome Hestor | Jerome Hestor |
 Steve HarmanDr. Martin's Assistant | Dr. Martin's Assistant |
 Ben LawsonWaiter | Waiter |
 Victor ParascosHelicopter Pilot | Helicopter Pilot |
| EEnrico MammarellaResort Manager | Resort Manager |
 Rachel Leigh AndersonBarbara | Barbara |
| DDave NemethWally Gilliams, TV Newscaster | Wally Gilliams, TV Newscaster |
 Thom FountainMaitre D' | Maitre D' |
| SScott McLeanSea Wasp Crewman | Sea Wasp Crewman |
 Vincent B. GorceBartender | Bartender |