Upcoming and Planned Aquariums in Japan｜Projects to Watch as of March 2026
Future aquarium projects are exciting, but they can be difficult to track because information changes quickly. Some projects already have a clear opening year and scale, while others are still at the concept stage with many details left open.
This guide organizes the most notable cases we could confirm through public sources as of March 24, 2026, separating them into confirmed upcoming openings, early concepts, and major redevelopments.
How This Guide Is Organized
- Operating aquariums are covered elsewhere and are not mixed into this list
- Projects are grouped by how concrete they currently are
- Opening dates, scale, and details may change as plans move forward
At a Glance
- Most concrete upcoming project: the new aquarium at TOKYO GIANTS TOWN
- Most distinctive concept-stage project: Mirai Kaiyokan by aquazoo
- Most important redevelopment to watch: the new Kasai Rinkai Aquarium project
1. A Confirmed Upcoming Project: The New Aquarium at TOKYO GIANTS TOWN
The clearest upcoming aquarium project at the moment is the new aquarium planned for TOKYO GIANTS TOWN in Inagi, Tokyo. The official concept page states that the aquarium and food facilities are scheduled to open in 2027, and a later official news release says the aquarium is planned to open during 2027.
What makes it stand out is its scale and its mixed-use concept. Official information describes a facility with roughly 2,000 tons of total water volume and a main tank of about 1,300 tons. A January 2026 update also states that the aquarium is planning a coral-reef-themed main tank and coral propagation tanks.
2. A Concept-Stage Project to Watch: Mirai Kaiyokan
A more speculative but highly distinctive project is Mirai Kaiyokan, introduced on the official aquazoo website. It is presented as a laboratory-style aquarium focused on the protection, care, and breeding of manatees.
The concept is especially notable because it aims to bring together the three living manatee species in one facility for both public viewing and research. At the time of writing, the official information does not make the future location or opening date concrete enough to call it a confirmed upcoming aquarium, so it is better understood as a concept-stage project.
3. A Redevelopment Worth Watching: Kasai Rinkai Aquarium
Not every major future project is a completely new aquarium. One of the most important redevelopment cases in Japan is the new Kasai Rinkai Aquarium project in Tokyo. According to the Tokyo Metropolitan Government's official redevelopment page, a new aquarium is being built on adjacent land next to the current site.
The official schedule points to a service start in September 2028. The new facility is planned at about 4,600 tons of total water volume, with updated exhibits and new learning and immersive features. The current glass dome building is also planned to be preserved after the new aquarium opens, making this a redevelopment story with architectural significance as well.
What to Watch Going Forward
- How firm the schedule is: an opening year is helpful, but an actual timetable is stronger
- How clearly the location is defined: confirmed sites and building scale matter
- How much official information exists: concept pages, government announcements, and project updates are more reliable than rumor-based reports
- Whether it is new or rebuilt: a major redevelopment can matter just as much as a brand-new aquarium
FAQ
What is the difference between a confirmed opening and a concept-stage aquarium?
A confirmed opening usually has a clearer opening schedule, project owner, and location. A concept-stage aquarium has a visible idea or vision, but the place, timing, or implementation details are still fluid.
When do ticket prices and opening hours usually become official?
In many cases, official ticket prices and opening hours are announced closer to launch. Earlier announcements often focus only on the concept, scale, or planned opening year.
Are redevelopment projects worth following too?
Yes. Even if a project is not a brand-new aquarium, a major redevelopment can significantly change the size, exhibits, and overall visitor experience.
Public Sources Used
Summary
As of March 2026, the most concrete upcoming aquarium project is the new aquarium at TOKYO GIANTS TOWN. Mirai Kaiyokan is still best understood as a concept, but it stands out for its originality. Kasai Rinkai Aquarium is not a brand-new project, yet its redevelopment is large enough to matter just as much for future aquarium watchers.
What to Read Next
If you want to explore operating aquariums now, head to the full directory. If you prefer theme-based comparisons, our other feature articles are a good next step.