George decides to take the family on holiday to Costa Rica where he will be filming a whale documentary, while Barbie and friends land summer jobs at a water park in Malibu.

After her boss is fired, Barbie is promoted with new responsibilities. Unfortunately, she learns that one of those responsibilities is that she has to fire Ken. Meanwhile, Skipper and Stacie join Chelsea on a quest to find a missing mermaid, but end up getting lost.

Barbie's friends struggle to adjust to her becoming their boss at Oceans Extreme. In Costa Rica, Stacie, Skipper and Chelsea close in on the missing mermaid.

Barbie and her friends create a plan to stop smugglers and save a baby whale. As a reward, Barbie gets a ticket to Costa Rica, where she joins her family to see the whales arrive.

On her first day back to school, Barbie learns that Golden Beach High's newest student is none other than Tammy, her opponent from the baking competition show.

Barbie offers to help Renee build her school basketball team by trying out, but she soon realizes that she is not as great as she thought she would be.

Ken asks Barbie to help him invite Harriet to a school dance. Despite her mixed feelings, Barbie agrees to do it, because what are friends for?

When Margaret hesitates to take a promotion at her job, Barbie and her sisters work together to prove to their mother that they can handle extra responsibilities.

Skipper borrows Barbie's jacket without permission and ends up misplacing it. The two sisters race around town trying to retrieve the jacket, which has their father's 20th anniversary gift to their mother in its pocket, but are always one step behind.

Barbie tries to help Skipper adjust to high school by inviting her to join her lunch table. When Skipper bonds with her friends, Barbie unexpectedly feels left out.

The Roberts family are driven to enter Malibu's annual Family of the Year contest, competing against the family that has won every year for the past decade: the Reardons.

Barbie and Skipper collaborate on their school community service project at the Water Park, but the two clash when Skipper does not put in an equal amount of effort.

The Roberts host their neighbors at the Dreamhouse when an earthquake causes a power outage. Meanwhile, Barbie and Skipper decide to raise funds for the destroyed library.

Barbie, Tammy and all of Golden Beach High team up to defeat their rivals, Empire Coast High—which tests Tammy's loyalties due to them being her former school.

On Halloween, after watching a scary vampire film, Chelsea and Stacie come to believe that Barbie and her friends are all vampires, when in fact they are trying to set up the Dreamhouse into a haunted house.

When the Roberts go on their annual camping trip, Barbie makes brownies that no one can resist, but forbids anyone from eating them until the second night around the campfire, per family tradition. When someone eats the entire batch the night before though, the Roberts clan band together to figure out "whodunit".

After the Roberts camper is totaled after rolling down a hill, to raise the money to replace it, Barbie and her sisters sign up to compete in a game show that is infamous for tearing families down.

Barbie feels horrible when outside commitments keep her from taking Chelsea to her first circus, so Barbie decides to make up for it by putting on a circus at the Dreamhouse.

The Dudes & Trey get into a fight that results in the Dudes befriending Barbie instead. Without the Dudes, Trey finds a friend in Ken when they bond over a video game.

To gain more popularity in school, Tammy decides to imitate Barbie. When it goes too far, Barbie begins to feel deprived of her individuality. Meanwhile, Trey struggles to find a birthday gift for his mother, while Stacie and Chelsea agree to babysit a fashionable macaw named Bella, and end up losing her. Their problems intersect when Bella lands up at the Reardons' home, and Trey's mother, mistaking it for Trey's gift, falls in love with her. How will the Roberts sisters retrieve her?

Just before a group chemistry project presentation, Barbie falls ill with a cold. However, she does not want to take a day off and tries to figure out some way to attend the presentation without letting her project partners down. Meanwhile, Trey fakes an illness to play hooky, but runs into trouble when the principal catches him out of school.

Aunt Adele's inn is haunted by a ghost of a miner.

With a new ice rink in town, Barbie and her friends put on a show to promote it. However, Nikki gets hurt before the show, and their only choice for a replacement is a mysterious yet skillful chicken-masked ice skater.

Barbie and friends take the camper out to spend some quality time together.

It is Christmas time at the Roberts House, but not all is holly jolly—Barbie and Ken cannot find the perfect gift for each other for Christmas, Stacie and Skipper take drastic measures to get a good gift for each other, and the whole family has to prevent Chelsea from finding and opening the presents before Christmas morning.

When Barbie, Teresa and Nikki are asked to write their school song, they learn a lesson in working out creative differences.