The “The Idolmaster SideM” and Seibuen Amusement Park collaboration event, “Super!! Retro Party,” will be held from October 30 to December 1, 2026.

This is the second collaboration following last year’s event. On October 31 and November 1, and November 22, featuring the cast, and a stamp rally in collaboration with Tokyo Joypolis will also be held.

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Event Overview for The Idolmaster SideM “Super!! Retro Rose Party”

The “Super!! Retro Rose Party,” a collaboration event between “The Idolmaster SideM” and Seibuen Amusement Park, will be held from October 30 to December 1, 2026. This is the second installment, following last year’s “Retro Rose Party.”

Set against the park’s Showa-era retro atmosphere, idols from 315 Production—dressed in retro suits—will make their appearance holding roses in full bloom this fall. According to the announcement, five units—DRAMATIC STARS, W, Café Parade, S.E.M, and F-LAGS—will participate.

*Content is subject to change or cancellation without notice.
*Event information and last-minute changes will be announced on the Seibuen Amusement Park official X account.

The Idolmaster SideM “Super!! Retroze ‘Special’ Party”

During the three-day event, a special event featuring the cast, the “Super!! Retroze ‘Special’ Party,” will be held. The venue is the special stage at Let’s Go! Leoland, and the event runs for one hour from 6:00 PM to 7:00 PM.

To participate, you must purchase a “1-Day Leisure Ticket with Event Admission Ticket,” priced at 10,000 yen (tax included). This package includes park admission, unlimited rides on attractions, an event admission ticket, and an original bonus item.

*Information regarding ticket sales and details will be announced at a later date.

Day 1: October 31, 2026 Cast

On October 31, the first day of the event, four cast members who portray the members of S.E.M. and Café Parade will join the two members of W on stage.

・Yusei Kikuchi (as Yusuke Aoi)
・Shosei Yamaya (as Kyosuke Aoi)
・Kento Ito (as Michio Hara)
・Yoshiki Nakajima (as Jiro Yamashita)

Day 2: Cast Members for November 1, 2026

On the second day, November 1, four cast members who portray members of DRAMATIC STARS and F-LAGS will take the stage.

・Sogo Nakamura (as Teru Tendou)
・Yufuko Sanpei (as Ryo Akizuki)
・Gakuto Urao (as Daigo Kabuto)
・Toshiya Hiruma (as Kazuki Tsukumo)

Day 3: November 22, 2026 Cast

On the final day, November 22, three cast members portraying members of Café Parade will take the stage.

・Sho Kano (as Yukihiro Kamiya)
・ Takuya Kodama (as Makio Uzuki)
・Daiki Kobayashi (as Saki Mizushima)

The Idolmaster SideM “We’re Working! Stamp Rally”

As part of a joint campaign with Tokyo Joypolis—which is collaborating with “The Idolmaster SideM” during the same period—the “Working Hard! Stamp Rally” will be held. Collect stamps from both venues to receive an original A5-size illustration card as a bonus.

*Locations for picking up the stamp rally card and claiming the special gift will be announced in due course.

Other Events for The Idolmaster SideM “Super!! Retro Rose Party”

Sales of original merchandise, collaboration food items, a rally tour of the park, and mini-games have been announced. Details for all of these have not yet been released as of the time of this writing.

*As of the time of writing, the contents of the GOODS, FOODS, RALLY, and other pages on the special website have not yet been released.

The Idolmaster SideM “Super!! Retro Rose Party” Operating Hours

Operating hours for the collaboration period have been announced for the first two days—October 30 and 31. Hours for November 1 and beyond will be announced sequentially.

*All prices include tax.
*Images are for illustrative purposes only.

The Idolmaster SideM Frequently Asked Questions About the “Super!! Retro Rose Party”

When and where will it be held?

It will be held from October 30 to December 1, 2026, at Seibuen Amusement Park in Tokorozawa City, Saitama Prefecture. The park will be closed on November 18 and November 25.

How can I participate in the special event?

You must purchase a “1-Day Leisure Ticket with Event Participation Pass” for 10,000 yen (tax included). Tickets are sold on a first-come, first-served basis and include park admission, unlimited rides, an event participation pass, and an original bonus item. Ticket sales and further details will be announced at a later date.

What is the reward for the stamp rally?

An A5-sized illustrated card. Collect stamps at both Seibuen Amusement Park and Tokyo Joypolis, then bring your completed card to the reward pickup location to receive it.

Have the merchandise and food offerings been announced?

As of this writing, they have not been announced. The park has announced plans to sell original merchandise, offer collaboration food items, hold a rally around the park, and host mini-games.

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For details, please visit the official website.
*Please note that the information in this article may be out of date; we kindly ask that you verify the details on the official website.

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