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Two new baby green sea turtles will be put on public display from September 19th. Their names will be announced at the unveiling ceremony on the first day of public display.
Sumida Aquarium (Location: Sumida-ku, Tokyo; General Manager: Rui Kawasumi) is pleased to announce that it will be opening to the public two baby green sea turtles born in the Ogasawara(hereinafter referred to as Ogasawara) on Saturday, September 19, 2026. An unveiling ceremony will be held on the first day of public viewing, where the names of the two turtles will be announced.
Since its opening in 2012, our aquarium has partnered with Ogasawara Village to participate in green sea turtle conservation activities. As part of this effort, we take in baby green sea turtles born in Ogasawara, carefully raise them for about a year until they are large enough to withstand predators, and then release them back into their home seas.
This year, we are once again taking care of two baby green sea turtles born this summer, and they will be on display at the "Ogasawara Base" on the 5th floor from Saturday, September 19th. An "unveiling ceremony" will be held at 10:00 a.m. on the first day of public display, where the names chosen by elementary school students from Ogasawara Village will be announced, and the moment they enter the tank for the first time will be shown. After the unveiling ceremony, you will be able to observe them eating and swimming energetically in the tank up close, and their carapace length and weight measurements will be posted, allowing you to see their growth over approximately one year.
In addition, to commemorate the public unveiling of the two sea turtles, we will be holding a paid program called "Aim for the Beach! Set Off to the Sea! A Parent-Child Journey Following the Green Sea Turtles," where you can learn about marine environmental issues from the perspective of green sea turtles, as well as a free workshop called "Sea Turtle Watching." We will also be selling a special dessert menu called "Welcome Baby Sea Turtles! Ogasawara Sundae" for two days only, on September 19th (Sat) and 20th (Sun).
Please note that the two green sea turtles, "Asahi" and "Yuhi" (*1), which have been on display for approximately one year since September 2025, will cease public viewing on Saturday, September 5th, and will be released back into the sea from a beach in Ogasawara Village by the animal care staff on Tuesday, September 8th. The departure of the two turtles into the sea will be live-streamed on the aquarium's official YouTube channel.
Sumida Aquarium is promoting "AQTION! (Action) *2," a sustainability initiative that aims to pass the baton to the future of our planet. We will continue to introduce information about the animals of the Ogasawara Ogasawara , including green sea turtles, through our exhibits and official social media accounts, providing opportunities for people to learn about the rich nature of the Ogasawara and conservation efforts.
1. Public viewing and unveiling of baby green sea turtles
We will be welcoming two baby green sea turtles born in Ogasawara this Ogasawara, and they will be on public display in a tank at "Ogasawara Base" for about a year. Next to the tank, we will also post growth records showing the carapace length and weight of the tiny babies, which will be measured regularly.
Sumida Aquarium has so far taken in 42 baby green sea turtles born in the Ogasawara, carefully raising them for about a year until they grew to a size where they were less vulnerable to predators, and then returning them to their home seas. The two turtles we are welcoming this time will be the 43rd and 44th.
Please keep a watchful eye on this baby Ogasawara turtle, which is about 7-8 cm long, so that it can return to the Ogasawara Islands in good health in about a year.
Public viewing period: September 19, 2026 (Saturday) to late August 2027 (tentative)
Exhibition location: " Ogasawara Base " in the Ogasawara area on the 5th floor
There are three feeding times a day. You can observe them eating up close.
The exhibits may be changed without notice depending on the health condition of the animals.
■ About the unveiling ceremony
You will get to see two baby green sea turtles entering the Sumida Aquarium tank for the first time. The animal care staff will explain their conservation efforts, measure the carapace length and weight of the two turtles, and announce the names they came up with, chosen by fifth-grade students from Ogasawara Elementary School in Ogasawara Village.
Date and Time: Saturday, September 19, 2026, 10:00 AM - 10:30 AM
Venue: " Ogasawara Base " in the Ogasawara area on the 5th floor
Participation fee: Free
Aquarium admission fee separate.
How to participate: Please gather at "Ogasawara Base" when the time comes.
The content may be changed without notice depending on the health condition of the animals.
2. About the "sunrise" and "sunset" that are returned to the sea of my hometown, the Ogasawara.
These are sibling green sea turtles born in Ogasawara on August 8, 2025 (Friday). They were put on public display at Sumida Aquarium on September 13, 2025 (Saturday), and many visitors watched them grow for about a year. Named "Asahi" (morning sun) and "Yuhi" (evening sun) by fifth-grade students at Ogasawara Elementary School in Ogasawara Village in 2025, with the theme of "Sharing the Charms of Ogasawara ," "Asahi" grew from a carapace length of approximately 7.3 cm and a weight of 69 g to a carapace length of 21.0 cm and a weight of 1,494 g, while "Yuhi" grew from a carapace length of approximately 6.6 cm and a weight of 53 g to a carapace length of 21.3 cm and a weight of 1,503 g (as of August 30, 2026 (Sunday)). The two turtles will be on display in the facility until Saturday, September 5, 2026. After a voyage of approximately 24 hours, they will be released back into the sea from the beach in Ogasawara Village on Tuesday, September 8, by the animal care staff who have watched over their growth.
■ The sunrise and sunset head towards the sea of their homeland. Live streaming of the moment of departure.
We will be live streaming the moment when the two horses, "Asahi" and "Yuhi," depart for the seas around the Ogasawara on our official YouTube channel.
Streaming date and time: Tuesday, September 8, 2026, starting at 9:45 AM (scheduled)
Streaming platform: Our official YouTube channel ( https://www.youtube.com/@SumidaAquarium/streams )
The broadcast time and content may change depending on the weather, the health of "Asahi" and "Yuhi," and the communication environment.
The streaming status is available on our official website X (We will announce it at https://x.com/Sumida_Aquarium.
3. Paid program: "Aim for the beach! Set off on a journey to the sea! A parent-child trip following the green sea turtles."
This parent-child program explores the coexistence of the natural environment and human life from the perspective of a green sea turtle. Parents and children work together in a board game format to follow the journeys of adult turtles heading to the beach to lay eggs and hatchlings heading to the sea immediately after hatching.
The setting is the Ogasawara Ogasawara, Japan's largest breeding ground for green sea turtles*. As you move across the map, you'll encounter various challenges that sea turtles actually face, such as marine debris and natural predators. Participants, working as a family, will discuss and consider what actions to take to address these challenges as they make their way to the goal, learning about marine animals and the environment in a fun way. Through four steps—"Know," "Experience," "Realize," and "Act"—the game provides an opportunity to think about what we can do to pass on life to the future and to take action.
Dates: September 19th (Sat) and 20th (Sun), 2026
Event times: Each session from 11:00 AM to 12:00 PM
Venue: 5th Floor Aqua Academy
Target audience: One elementary school child and one parent/guardian (2 people per group)
Capacity: 5 groups (10 people) per session / First-come, first-served basis
Participation fee: 1,000 yen per group
Aquarium admission fee separate.
How to participate: Sales website
Please register in advance via the following link: ( https://www.asoview.com/channel/ticket/Pwzf74k1E8/ticket0000043609/) .
Recruitment starts: September 3, 2026 (Thursday) 2:00 p.m.
4. Free workshop: "Sea Turtle Watching"
This workshop allows you to create a life-sized craft model of a newly hatched green sea turtle baby. You can wear it on your wrist like a watch and compare its size to the babies in the aquarium.
Event period: September 19th (Sat) - September 30th (Wed), 2026
Opening hours: Weekdays / 11:00 AM - 4:00 PM (Last entry: 3:30 PM)
Weekends and public holidays: 10:00 AM to 5:00 PM (Last entry: 4:30 PM)
Venue: 5th floor "Aqua Academy"
Participation fee: Free
Aquarium admission fee separate.
How to participate: Register at "Aqua Academy" on the day of the event.
The event will be held from 1 PM to 5 PM on Saturday, September 19th and Sunday, September 20th.
5. Limited-time sale for 2 days only: "Welcome Baby Sea Turtle! Ogasawara Sunday"
To commemorate the public viewing of the baby green sea turtles, this dessert menu will be available for two days only. It features vanilla soft serve ice cream made with salt from the Ogasawara Islands, topped with acerola jelly and drizzled with passion fruit sauce from the Ogasawara Islands. Enjoy the charm of Ogasawara with this dessert, complete with a pick designed to resemble a baby green sea turtle.
Sales dates: September 19th (Sat) and 20th (Sun), 2026
Sales location: Penguin Café on the 5th floor
Price: 920 yen (tax included)
6. "AQTION!" - Activities to create the future of Earth
This is an initiative to create a better future for our planet, originating from Sumida Aquarium and Kyoto Aquarium. It's an action by the aquariums, and with the hope of connecting it to everyone's actions, it's called "AQTION!", meaning "ACTION that starts from AQUARIUM".
Aquariums, where visitors can experience and closely observe the diverse lives of various animals, aim to inspire reflection on the global environment and the importance of life, thereby nurturing the power of children to create the future. Our green sea turtle conservation activities in collaboration with Ogasawara Village are one of the activities of "AQTION!".
■Sumida Aquarium "AQTION!" Official Website: https://www.sumida-aquarium.com/initiative/aqtion/
7. Conservation activities for baby green sea turtles
The Ogasawara Islands, registered as a World Natural Heritage site in June 2011, are the largest nesting ground for green sea turtles in Japan, and various conservation efforts are underway there. Sumida Aquarium supports the activities of Ogasawara Village and participates in an activity* in which it takes care of baby green sea turtles for about a year, raising them before releasing them back into the Ogasawara sea, so that visitors can see their adorable appearance, growth process, and rarity. The green sea turtles in our care are on display to visitors at the "Ogasawara Base" on the 5th floor of Sumida Aquarium. Even small children can observe the green sea turtles from various angles.
This is a sea turtle joint breeding program organized by Everlasting Nature, a certified NPO that conducts sea turtle conservation activities at the Ogasawara Marine Center, which is owned by Ogasawara Village.
■ About Green Sea Turtles
While young, they are omnivorous, but as they grow, they mainly feed on seaweed and seagrass, reaching a maximum carapace length of about 100 cm and a weight of about 200 kg. They lay eggs on the beach every year from spring to summer, and the eggs hatch about two months later. They lay more than 100 eggs at a time, but only a very small number survive for more than a year, and it is said that it takes about 40 years for a green sea turtle to reach maturity.
