- Johnny - Captain of the Mayship
- Janus - The mascot of the Jellyfish Pirates, a black cat who is anything but unlucky.
- Febe - The blonde record keeper, dressed in pink.
- March - The youngest of the crew dressed in bright red, always carries a stuffed penguin with her.
- April - Co-pilot of the Mayship and May's best friend, sometimes joins May for a victory-dance after a battle.
- May - First mate of the Mayship and infatuated with the captain.
- June - The purple-haired navigator dressed in amaranth.
- July - Characterised by her eye-patch and sword, July is believed to be the fourth-strongest of the crew, after Dizzy, Johnny, and May. Her uniform is indigo.
- Augus - Another of the Jellyfish Pirate's proud warriors, dressed in dark purple.
- Sephy - The cleaner of the crew who keeps the Mayship spick-and-span and smelling lemony-fresh. She is characterized by her always-shut eyes and purple uniform.
- Octy - The look-out and official telescope-girl, with green hair that obstructs her eyes and a cyan uniform.
- Novel - The crew's mechanic that pilots a small red mecha, dressed in orange and wearing goggles.
- Dizzy - Does the laundry and shopping
- Leap - The oldest of the crew, Leap is a large and elderly woman that cooks for the crew and looks after March. She is named after the event Leap Year.
- Dolphin-kun - Also known as Mr. Dolphin, he is May's aquatic friend and battle partner, kept in a fish tank aboard the airship.
The most common Jellyfish crew outfit is a sailor top that shows the midriff, jean shorts and a bandana. However, each of the girls have their own versions of their uniform, and in Xrd, their outfits are further diversified from each other, with some members wearing entirely different headgear and all of them (excluding April) now sporting unique color schemes.
In Xrd, the collars of the uniforms are each marked with a roman numeral corresponding to the month the Jellyfish Pirate is named after (while Leap's collar is marked with "LY").
- In Arc System Works' BlazBlue, the female lead, Noel Vermillion, is pursed by Litchi Faye-Ling, who forces her to don bizarre outfits upon catching up to her. One of these outfits is a Jellyfish Pirates' uniform with May's hat.