Oki Mariner Crew

The Oki Mariner Crew (隠岐マリナークルー) are a team of Heroes led by Captain Selkie.

Overview
The Oki Mariner Crew specializes in maritime missions, occasionally receive requests for help from the Japan Coast Guard. When they are not on a mission, their daily grind consists of training, patrols and cleaning the Oki Mariner ship.

The crew is made up of five members and their hero costumes are related to the sea: Selkie, the hero and captain of the Oki Mariner, wears a costume based on a diver's suit, while his sidekicks wear sleeveless sailor suits.

Strength
The Oki Mariner Crew is a fairly efficient group of heroes for offshore missions. Their ship has the means to explore and patrol the sea and the rugged shores of the Japanese archipelago, as well as board suspicious ships. By combining the ship's radar with the crew's Quirks they can detect the position of their targets.

Vs. Hero Killer Arc
Tsuyu Asui choses to do her Hero Agency Internships with the Okie Mariner crew because she wanted to work somewhere that would match well with her Quirk. Froppy spends most of her internship training and doing tasks to keep the Oki Mariner clean. Despite this, she maintains a good relationship with the hero Selkie and his sidekick Sirius.

One day, the Oki Mariner receives a request from Japan coast guard asking them to assist in apprehending smugglers. Although at first Selkie and several crew’s members fall into a trap, Tsuyu and Sirius manage to locate the smugglers' ship, saving enough time for Selkie to reach the location and defeat the villains.

Shie Hassaikai Arc
Students in class 1-A have permission to participate in Hero Work-Studies. However, due to the increase in villain activity, the U.A. faculty members allow Hero Offices with proven track records of employing students in the past to be allowed to take on first-year students.

Tsuyu wanted to do her Work Studies with Selkie and the Oki Mariner crew, but because they do not have the conditions demanded by the U.A., her request was denied, later opting for Ryukyu.

Endeavor Agency Arc
The Oki Mariner is chasing a stateless ship suspected of smuggling when one of the crew of the latter injects himself a Trigger to enhance his Quirk and generate an extensive Smokescreen with which to escape and hide in the Verize Islands. Considering how complicated the search for the ship in that area is and the danger posed by the drug Trigger, Captain Selkie sends a request for help to the hero Ryukyu, who meets with them along with her sidekicks Nejire, Ochaco, and Tsuyu. The Oki Mariner Crew is happy to see their former intern again and to know that she is becoming quite a hero.

After explaining the situation and letting the girls relax for a while, the two teams go out in search of the smugglers, finding them within a few hours. They use again a smokescreen to hide, but the heroes had foreseen this, and Selkie boards the ship and defeats two of the smugglers, but the leader had taken advantage of the smoke to deploy a seaplane with which to escape with the drugs. With the help of Sirius, Ochaco manages to board the seaplane and defeat the last villain, and with the help of Ryukyu and Nejire, she manages to prevent the plane from crashing into the ocean.

After the mission ended successfully, Selkie informs Ryukyu that, according to police interrogations, the smugglers were only in charge of transporting the drug to the country of Otheon, although they do not about the intention for the drugs and who hired them. Despite this, Selkie believes that they should feel glad that they have stopped that plan.

Trivia

 * In the manga, the Oki Mariner Crew appears briefly in Tsuyu's flashback when she talks about her experiences during the Hero Agency Internships, though only the Oki Mariner Ship and the silhouettes of two crew members are shown. Later on, she mentions captain Selkie.