Yumiko Samejima (鮫島 弓子 Samejima Yumiko) is the caterer for the Antarctic expeditions held by the Antarctic Challenge Foundation. A self-proclaimed "Antarctic chef", she is originally from Okinawa.
Yumiko tends to act "tsundere" towards another expeditioner, Toshio Zaizen.
Yumiko debuts in episode 2, in which she attends an informal Antarctic Challenge Foundation meet-up in Shinjuku with the other expeditioners that were confirmed to return. The meet-up is gatecrashed by Shirase Kobuchizawa and her friends, who then try to escape. Yumiko chases after one of Shirase's friends, Hinata Miyake, until the latter crashes into Shirase and her other friend, Mari Tamaki. She and Kanae Maekawa take the girls to a café; both tell Shirase once more that they can't take her along, and even refuse one million yen from her. Despite that, Yumiko continues to voice doubts about the expedition going ahead, to which Kanae responds that they will find a way.
Yumiko next appears in episode 7, seeing all four girls (including Yuzuki Shiraishi) on board the Penguin Manju Go. She assigns them with the task of loading supplies on-board the ship. After the ship departs in episode 8, and the girls report to the ship's galley, Yumiko requests for the potatoes to be peeled. When the deck opens for training, Yumiko joins them there and shows them which direction to run. She also reminds the girls that it is important to have stamina, before running off herself.
After the expeditioners arrive at Showa Station in episode 10, Yumiko assigns some catering-related jobs to the girls. First, she has them bring specific supplies from the warehouse. Then, she assigns Mari and Hinata with the task of defrosting some raw chicken, while Yuzuki and Shirase help bake cakes.
In episode 12, Yumiko hosts an "Antarctic barbecue" before the expeditioners leave on the snowcats for the inland station. In the final episode, on the day the girls leave, Yumiko gives them some cupcakes that she made using leftover ingredients.
Yumiko also caters as part of her day job, but the organization she caters for remains unclear. It is also implied that Yumiko got married in between the two expeditions.
- The name Yumiko means "archery bow" (弓) (yumi) and "child" (子) (ko).
- Yumiko's surname Samejima means "shark" (鮫) (same) and "island" (島) (shima/jima).