Princess

A Princess is a female heir to the throne. She is usually a daughter of a King and/or Queen and is in a position where she legitimately could inherit her country's throne.

Overview
A Princess is in line for the throne if she is the oldest heir, although if she is approximately the same age as a male heir, he may have the preference. If the King dies or retires without having a male heir, the princess will become the ruler and take over as Queen.

In One Piece
Currently, very few princesses made an appearance in One Piece.

The most notable princess is Nefertari Vivi of Alabasta who traveled with the Straw Hat Pirates during the Alabasta Saga. Vivi does not follow the real world tradition of a princess in many ways, in the sense she can be more like a commoner at times than royalty.

The second prominent princess is Shirahoshi of Ryugu Kingdom, who is also considered to be the Mermaid Princess, a legendary figure who can summon Sea Kings.

Mansherry is the princess of Tontatta Kingdom, and accordingly, she is spoiled, cruel and selfish, though still a comrade for her people to want to save her. In truth, she is kind, caring and loyal to everyone, her negative attitude being directed only to Leo out of a tsundere-love.

Rebecca is the lost princess of the Riku royal family of Dressrosa that was overthrown by Doflamingo and is now forced to be a gladiator; her mother and aunt were the first and second crown princesses of the country before Doflamingo overthrew them. Though Doflamingo remains standing, when his tyranny was revealed, Rebecca, Scarlett and Viola's names were all cleared from their negative reputations.

Hatchan met the Goldfish Princess in his seafloor stroll.

Current Princesses

 * Nefertari Vivi is the princess of the Alabasta Kingdom.
 * Goldfish Princess is the princess of the Goldfish Kingdom.
 * Shirahoshi is the princess of the Ryugu Kingdom.
 * Mansherry is the princess of the Tontatta Kingdom.

Former Princesses

 * The previous Poseidon, who was the first known "Mermaid Princess" of Ryugu Kingdom.
 * Scarlett is the daughter of king Riku Dold III and the first crown princess of Dressrosa before her assumed and actual demise at the hands of Diamante.
 * Viola is the daughter of king Riku Dold III and the second crown princess of Dressrosa before swearing her loyalty to the Donquixote Pirates.
 * Rebecca is the lost princess of the fallen Riku royal family of Dressrosa.

Princess as an Epithet

 * Perona: Ghost Princess
 * Boa Hancock: Snake Princess
 * Shirahoshi: Mermaid Princess
 * Rebecca: Phantom Princess